Aminoadamantyl nitrate compounds and their use to treat cns disorders

ABSTRACT

The present disclosure provides adamantyl compounds having one or more amine groups and one or more nitrate groups. The aminoadamantyl nitrate compounds can be used to treat disorders of the central nervous system, including neurodegenerative and non-neurodegenerative diseases.

BACKGROUND OF THE DISCLOSURE

The N-methyl-D-aspartate receptor (also known as the NMDA receptor orNMDAR) is an excitatory glutamate receptor and ion-channel protein foundin neurons in the central nervous system (CNS). Activation of the NMDAreceptor requires the binding of glutamate (or aspartate or NMDA, bothweaker stimulants), which is released following depolarization of thepresynaptic neuron, and the binding of glycine (or D-serine, a strongerco-agonist) for efficient opening of the ion-channel part of thereceptor. Activation of the NMDAR produces an excitatory postsynapticpotential that results in the opening of a transmembrane ion channel andflow of non-selective cations through it. While the opening and closingof the ion channel is primarily gated by ligand binding, the currentflow through the ion channel is voltage-dependent. Extracellularmagnesium (Mg²⁺) ions can bind to an allosteric site in the NMDARchannel at resting membrane potential, thereby blocking the passage ofother cations through the open ion channel. Depolarization of thepostsynaptic membrane in the scale of milliseconds mediated by anothertype of ionotropic glutamate receptor, the AMPA receptor, dislodges andrepels the Mg²⁺ ions from the pore, thereby allowing a voltage-dependentflow of sodium (Na⁺) ions and calcium (Ca²⁺) ions into the cell andpotassium (K⁺) ions out of the cell. The influx of Ca²⁺ triggersintracellular signaling pathways with Ca²⁺ acting as a second messenger.

The ion channel of an NMDA receptor opens and remains open only when theco-agonists glutamate and glycine are bound to the receptor and thepostsynaptic membrane is depolarized to remove the voltage-dependentchannel block by Mg²⁺. This property of the NMDA receptor is animportant cellular mechanism for synaptic plasticity and long-termpotentiation underpinning it. NMDAR-mediated neurotransmission is theprimary interneuronal communication underlying synaptic plasticity.

NMDA receptors are located synaptically and extrasynaptically. Theproportion of synaptic NMDARs increases with development, although asignificant number of extrasynaptic NMDARs remains in adulthood. Ca²⁺influx through activated synaptic NMDARs is important for controllingsynaptic plasticity and synapse formation underlying memory, learningand formation of neural networks during development of the CNS. Underpathological conditions, however, excessive extracellular levels ofglutamate cause overstimulation of extrasynaptic NMDARs and continuousdepolarization of neurons, resulting in excessive Ca²⁺ influx intoneurons. Excessive intracellular Ca²⁺ concentration disrupts calciumhomeostasis and initiates a cascade of signaling pathways, leading toupregulation of neuronal nitric oxide synthase, dysfunction ofmitochondria, production of reactive oxygen species, deregulation ofoxidative phosphorylation, endoplasmic reticulum stress, release oflysosomal enzymes, and ultimately neuronal death. Overactivation ofextrasynaptic NMDARs causing excessive influx of Ca²⁺ can lead toexcitotoxicity implicated in neurodegenerative disorders such asAlzheimer's disease, Huntington's disease and Parkinson's disease.Alzheimer's disease is the most common neurodegenerative disorder andthe most common form of dementia, afflicts at least 18 million peopleworldwide, and will become more prevalent as the number of elderlypeople grows.

SUMMARY OF THE DISCLOSURE

The disclosure provides aminoadamantyl nitrate compounds that areselective uncompetitive antagonists of activated extrasynaptic NMDAreceptors. In some embodiments, the aminoadamantyl nitrate compounds areof Formula I:

and pharmaceutically acceptable salts, solvates, hydrates, clathrates,polymorphs and stereoisomers thereof, wherein Y is a nitrate-containinggroup and R¹, R², R³, R⁴, R⁵, X and m are as defined elsewhere herein.

In other embodiments, the aminoadamantyl nitrates are of Formulas II andIII:

and pharmaceutically acceptable salts, solvates, hydrates, clathrates,polymorphs and stereoisomers thereof, wherein Y is a nitrate-containinggroup and R¹, R², R³, R⁴, R⁵, X and m are as defined elsewhere herein.

The aminoadamantyl nitrate compounds can be used to treat a broad rangeof neurodegenerative and other CNS disorders, including Alzheimer'sdisease, vascular dementia, Huntington's disease, Parkinson's disease,cerebral ischemia, traumatic brain injury, epilepsy and autism spectrumdisorder.

BRIEF DESCRIPTION OF THE DRAWINGS

A better understanding of features and advantages of the presentdisclosure will be obtained by reference to the following detaileddescription, which sets forth illustrative embodiments of thedisclosure, and the accompanying drawings.

FIG. 1 describes the synthesis of various aminoadamantyl nitratecompounds.

DETAILED DESCRIPTION OF THE DISCLOSURE

While various embodiments of the present disclosure are describedherein, it will be obvious to those skilled in the art that suchembodiments are provided by way of example only. Numerous modificationsand changes to, and variations and substitutions of, the embodimentsdescribed herein will be apparent to those skilled in the art withoutdeparting from the disclosure. It is understood that variousalternatives to the embodiments described herein can be employed inpracticing the disclosure. It is also understood that every embodimentof the disclosure can optionally be combined with any one or more of theother embodiments described herein which are consistent with thatembodiment.

Where elements are presented in list format (e.g., in a Markush group),it is understood that each possible subgroup of the elements is alsodisclosed, and any one or more elements can be removed from the list orgroup.

It is also understood that, unless clearly indicated to the contrary, inany method described or claimed herein that includes more than one actor step, the order of the acts or steps of the method is not necessarilylimited to the order in which the acts or steps of the method arerecited, but the disclosure encompasses embodiments in which the orderis so limited.

It is further understood that, in general, where an embodiment in thedescription or the claims is referred to as comprising one or morefeatures, the disclosure also encompasses embodiments that consist of,or consist essentially of, such feature(s).

It is also understood that any embodiment of the disclosure, e.g., anyembodiment found within the prior art, can be explicitly excluded fromthe claims, regardless of whether or not the specific exclusion isrecited in the specification.

Headings are included herein for reference and to aid in locatingcertain sections. Headings are not intended to limit the scope of theembodiments and concepts described in the sections under those headings,and those embodiments and concepts may have applicability in othersections throughout the entire disclosure.

All patent literature and all non-patent literature cited herein areincorporated herein by reference in their entirety to the same extent asif each patent literature or non-patent literature were specifically andindividually indicated to be incorporated herein by reference in itsentirety.

I. Definitions

As used in the specification and the appended claims, the indefinitearticles “a” and “an” and the definite article “the” can include pluralreferents as well as singular referents unless specifically statedotherwise or the context clearly dictates otherwise.

The term “about” or “approximately” means an acceptable error for aparticular value as determined by one of ordinary skill in the art,which depends in part on how the value is measured or determined. Incertain embodiments, the term “about” or “approximately” means withinone standard deviation. In some embodiments, when no particular marginof error (e.g., a standard deviation to a mean value given in a chart ortable of data) is recited, the term “about” or “approximately” meansthat range which would encompass the recited value and the range whichwould be included by rounding up or down to the recited value as well,taking into account significant figures. In certain embodiments, theterm “about” or “approximately” means within 20%, 15%, 10% or 5% of thespecified value. Whenever the term “about” or “approximately” precedesthe first numerical value in a series of two or more numerical values orin a series of two or more ranges of numerical values, the term “about”or “approximately” applies to each one of the numerical values in thatseries of numerical values or in that series of ranges of numericalvalues.

Whenever the term “at least” or “greater than” precedes the firstnumerical value in a series of two or more numerical values, the term“at least” or “greater than” applies to each one of the numerical valuesin that series of numerical values.

Whenever the term “no more than” or “less than” precedes the firstnumerical value in a series of two or more numerical values, the term“no more than” or “less than” applies to each one of the numericalvalues in that series of numerical values.

The term “pharmaceutically acceptable” refers to a substance (e.g., anactive ingredient or an excipient) that is suitable for use in contactwith the tissues and organs of a subject without excessive irritation,allergic response, immunogenicity and toxicity, is commensurate with areasonable benefit/risk ratio, and is effective for its intended use. A“pharmaceutically acceptable” excipient or carrier of a pharmaceuticalcomposition is also compatible with the other ingredients of thecomposition.

The term “therapeutically effective amount” refers to an amount of acompound that, when administered to a subject, is sufficient to preventdevelopment of, or to alleviate to some extent, the medical conditionbeing treated or one or more symptoms associated with the condition. Theterm “therapeutically effective amount” also refers to an amount of acompound that is sufficient to elicit the biological or medical responseof a cell, tissue, organ, system, animal or human which is sought by aresearcher, veterinarian, medical doctor or clinician.

The terms “treat”, “treating”, and “treatment” include alleviating orabrogating a medical condition or one or more symptoms associated withthe condition, and alleviating or eradicating one or more causes of thecondition. Reference to “treatment” of a condition is intended toinclude prevention of the condition. The terms “prevent”, “preventing”,and “prevention” include precluding or delaying the onset of a medicalcondition or one or more symptoms associated with the condition,precluding a subject from acquiring a condition, and reducing asubject's risk of acquiring a condition. The term “medical conditions”includes diseases and disorders.

The terms “diseases” and “disorders” are used interchangeably herein.

The term “subject” refers to an animal, including but not limited to amammal, such as a primate (e.g., a human, a chimpanzee or a monkey), arodent (e.g., a rat, a mouse, a guinea pig, a gerbil or a hamster), alagomorph (e.g., a rabbit), a swine (e.g., a pig), an equine (e.g., ahorse), a canine (e.g., a dog) or a feline (e.g., a cat). The terms“subject” and “patient” are used interchangeably herein in reference,e.g., to a mammalian subject, such as a human subject.

The term “compound” encompasses salts, solvates, hydrates, clathratesand polymorphs of that compound. A “solvate” of a compound includes astoichiometric or non-stoichiometric amount of a solvent (e.g., water,acetone or an alcohol [e.g., ethanol]) bound non-covalently to thecompound. A “hydrate” of a compound includes a stoichiometric ornon-stoichiometric amount of water bound non-covalently to the compound.A “clathrate” of a compound contains molecules of a substance (e.g., asolvent) enclosed in the crystal structure of the compound. A“polymorph” of a compound is a crystalline form of the compound. Thespecific recitation of “salt”, “solvate”, “hydrate”, “clathrate” or“polymorph” with respect to a compound in certain instances of thedisclosure shall not be interpreted as an intended omission of any ofthese forms in other instances of the disclosure where the term“compound” is used without recitation of any of these forms, unless thecontext clearly indicates otherwise.

The terms “halogen”, “halide” and “halo” refer to fluorine/fluoride,chlorine/chloride, bromine/bromide and iodine/iodide.

The term “alkyl” refers to a linear or branched, saturated monovalenthydrocarbon radical, wherein the alkyl group can optionally besubstituted with one or more substituents as described herein. Incertain embodiments, an alkyl group is a linear saturated monovalenthydrocarbon radical that has 1 to 10 (C₁₋₁₀) or 1 to 6 (C₁₋₆) carbonatoms, or is a branched saturated monovalent hydrocarbon radical thathas 3 to 10 (C₃₋₁₀) or 3 to 6 (C₃₋₆) carbon atoms. As an example, theterm “C₁₋₆ alkyl” refers to a linear saturated monovalent hydrocarbonradical of 1 to 6 carbon atoms or a branched saturated monovalenthydrocarbon radical of 3 to 6 carbon atoms. Linear C₁₋₆ and branchedC₃₋₆ alkyl groups may also be referred to as “lower alkyl”. Non-limitingexamples of alkyl groups include methyl, ethyl, propyl (includingn-propyl and isopropyl), butyl (including all isomeric forms, such asn-butyl, isobutyl, sec-butyl and tert-butyl), pentyl (including allisomeric forms, such as n-pentyl), and hexyl (including all isomericforms, such as n-hexyl).

The terms “alkylene” and “-alkyl-” refer to a divalent alkyl group,which can optionally be substituted with one or more substituents asdescribed herein.

The term “heteroalkyl” refers to a linear or branched, saturatedmonovalent hydrocarbon group containing one or more heteroatomsindependently selected from O, N and S. In some embodiments, one or moreheteroatoms are in the main chain of the linear or branched hydrocarbongroup. The terms “heteroalkylene” and “-heteroalkyl-” refer to adivalent heteroalkyl group. A heteroalkyl group and a-heteroalkyl- groupcan optionally be substituted with one or more substituents as describedherein. Examples of heteroalkyl and -heteroalkyl-groups include withoutlimitation —(CH₂)_(m)—(O or S)—(CH₂)_(n)CH₃ and —(CH₂)_(m)—(O orS)—(CH₂)_(p)—, wherein m is 1, 2, or 3, n is 0, 1 or 2, and p is 1, 2 or3.

The term “alkoxy” refers to an —O-alkyl group, which can optionally besubstituted with one or more substituents as described herein.

Examples of —O-heteroalkyl and —O-heteroalkyl- groups include withoutlimitation ethylene glycol groups and polyethylene glycol (PEG) groups,including but not limited to —(OCH₂CH₂)_(n)—OR and —(OCH₂CH₂)_(n)O—wherein R is hydrogen or alkyl and in is 1, 2 or 3. It is understoodthat for a —O-heteroalkyl-ONO group, when the —O-heteroalkyl- group isan ethylene glycol or PEG group, the terminal oxygen atom of theethylene glycol or PEG group is part of the nitrate (—ONO₂) group. An—O-heteroalkyl group and an —O-heteroalkyl- group can optionally besubstituted with one or more substituents as described herein.

The term “haloalkyl” refers to an alkyl group that is substituted withone or more halogen/halide atoms. A haloalkyl group can optionally besubstituted with one or more additional substituents as describedherein. Examples of haloalkyl groups include without limitationfluoroalkyl groups, such as —CH₂F, —CHF₂, and —(CH₂)_(n)CF₃, andperfluoroalkyl groups such as —CF₃ and —(CF₂)_(n)CF— wherein n is 1, 2,3, 4 or 5.

The term “-alkylaryl” refers to an alkyl group that is substituted withone or more aryl groups. An -alkylaryl group can optionally besubstituted with one or more additional substituents as describedherein.

The term “cycloalkyl” refers to a cyclic saturated, bridged ornon-bridged monovalent hydrocarbon radical, which can optionally besubstituted with one or more substituents as described herein. Incertain embodiments, a cycloalkyl group has from 3 to 10 (C₃₋₁₀), orfrom 3 to 8 (C₃₋₈), or from 3 to 6 (C₃₋₆) carbon atoms. Non-limitingexamples of cycloalkyl groups include cyclopropyl, cyclobutyl,cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, norbornyl, decalinyland adamantyl. The term “-cycloalkyl-” refers to a divalent cycloalkylgroup, which can optionally be substituted with one or more substituentsas described herein.

The terms “heterocyclyl” and “heterocyclic” refer to a monocyclicnon-aromatic group or a multicyclic group that contains at least onenon-aromatic ring, wherein at least one non-aromatic ring contains oneor more heteroatoms independently selected from O, N and S.

The non-aromatic ring containing one or more heteroatoms may be attachedor fused to one or more saturated, partially unsaturated or aromaticrings. In certain embodiments, a heterocyclyl or heterocyclic group hasfrom 3 to 10, or 3 to 8, or 3 to 6 ring atoms. In some embodiments, aheterocyclyl or heterocyclic group is a monocyclic, bicyclic ortricyclic ring system, which may include a fused or bridged ring system,and in which nitrogen or sulfur atoms can optionally be oxidized,nitrogen atoms can optionally be quaternized, and one or more rings maybe fully or partially saturated, or aromatic. A heterocyclyl orheterocyclic group may be attached to the main structure at anyheteroatom or carbon atom which results in the creation of a stablecompound. Examples of heterocyclyl or heterocyclic groups includewithout limitation azepinyl, azetidinyl, aziridinyl, benzodioxanyl,benzodioxolyl, benzofuranonyl, benzopyranonyl, benzopyranyl,benzotetrahydrofuranyl, benzotetrahydrothienyl, benzothiopyranyl,β-carbolinyl, chromanyl, decahydroisoquinolinyl,dihydrobenzisothiazinyl, dihydrobenzisoxazinyl, dihydrofuryl,dihydropyranyl, dihydropyrazinyl, dihydropyridinyl, dihydropyrazolyl,dihydropyrimidinyl, dihydropyrrolyl, dioxolanyl, dithianyl, furanonyl,imidazolidinyl, imidazolinyl, indolinyl, indolizinyl,isobenzotetrahydrofuranyl, isobenzotetrahydrothienyl, isochromanyl,isoindolinyl, isothiazolidinyl, isoxazolidinyl, morpholinyl,octahydroindolyl, octahydroisoindolyl, oxazolidinonyl, oxazolidinyl,oxiranyl, piperazinyl, piperidinyl, 4-piperidonyl, pyrrolidinyl,pyrrolinyl, quinuclidinyl, tetrahydrofuryl, tetrahydrofuranyl(oxolanyl), tetrahydroisoquinolinyl, tetrahydropyranyl,tetrahydrothienyl (tetrahydrothiophenyl, thiolanyl), thiamorpholinyl(thiomorpholinyl), thiazolidinyl and 1,3,5-trithianyl. The term“-heterocyclyl-” refers to a divalent heterocyclyl group. A heterocyclylor heterocyclic group, and a-heterocyclyl- group, can optionally besubstituted with one or more substituents as described herein.

The term “aryl” refers to a monocyclic aromatic hydrocarbon group or amulticyclic group that contains at least one aromatic hydrocarbon ring.In certain embodiments, an aryl group has from 6 to 10 ring atoms.Non-limiting examples of aryl groups include phenyl, naphthyl,fluorenyl, azulenyl, anthryl, phenanthryl, biphenyl and terphenyl. Thearomatic hydrocarbon ring of an aryl group may be attached or fused toone or more saturated, partially unsaturated or aromatic rings—e.g.,dihydronaphthyl, indenyl, indanyl and tetrahydronaphthyl (tetralinyl).The term “-aryl-” refers to a divalent aryl group. An aryl group and an-aryl- group can optionally be substituted with one or more substituentsas described herein.

The term “heteroaryl” refers to a monocyclic aromatic group or amulticyclic group that contains at least one aromatic ring, wherein atleast one aromatic ring contains one or more heteroatoms independentlyselected from O, N and S. The heteroaromatic ring may be attached orfused to one or more saturated, partially unsaturated or aromatic ringsthat may contain only carbon atoms or that may contain one or moreheteroatoms. A heteroaryl group may be attached to the main structure atany heteroatom or carbon atom which results in the creation of a stablecompound. In certain embodiments, a heteroaryl group has from 5 to 10ring atoms. Examples of monocyclic heteroaryl groups include withoutlimitation pyrrolyl, pyrazolyl, pyrazolinyl, imidazolyl, oxazolyl,isoxazolyl, thiazolyl, thiadiazolyl, isothiazolyl, furanyl, thienyl(thiophenyl), oxadiazolyl, triazolyl, tetrazolyl, pyridyl, pyridonyl,pyrazinyl, pyrimidinyl, pyridazinyl, pyridazinonyl and triazinyl.Non-limiting examples of bicyclic heteroaryl groups include indolyl,benzothiazolyl, benzothiadiazolyl, benzoxazolyl, benzisoxazolyl,benzothienyl (benzothiophenyl), quinolinyl, tetrahydroisoquinolinyl,isoquinolinyl, benzimidazolyl, benzotriazolyl, indolizinyl,benzofuranyl, isobenzofuranyl, chromonyl, coumarinyl, cinnolinyl,quinazolinyl, quinoxalinyl, indazolyl, naphthyridinyl, phthalazinyl,quinazolinyl, purinyl, pyrrolopyridinyl, furopyridinyl, thienopyridinyl,dihydroisoindolyl and tetrahydroquinolinyl. Examples of tricyclicheteroaryl groups include without limitation carbazolyl, benzindolyl,dibenzofuranyl, phenanthrollinyl, acridinyl, phenanthridinyl, xanthenyland phenothiazinyl. The term “-heteroaryl-” refers to a divalentheteroaryl group. A heteroaryl group and a -heteroaryl- group canoptionally be substituted with one or more substituents as describedherein.

Each group described herein (including without limitation monovalent anddivalent alkyl, heteroalkyl, —O-alkyl, —O-heteroalkyl, alkylaryl,cycloalkyl, heterocyclyl, aryl and heteroaryl), whether as a primarygroup or as a substituent group, can optionally be substituted with oneor more substituents. In certain embodiments, each group describedherein can optionally be substituted with 1, 2, 3, 4, 5 or 6substituents independently selected from halide, cyano, nitro, nitrate,hydroxyl, sulfhydryl (—SH), —NH₂, —OR¹¹, —SR¹¹, —NR¹²R¹³, —C(═O)R¹¹,—C(═O)OR¹¹, —OC(═O)R¹¹, —C(═O)NR¹²R¹³, —NR¹²C(═O)R¹³, —OC(═O)OR¹¹,—OC(═O)NR¹²R¹³, —NR¹²C(═O)OR¹¹, —NR¹¹C(═O)NR¹²R¹³, alkyl, haloalkyl,cycloalkyl, heterocyclyl, aryl and heteroaryl, wherein:

-   -   R¹¹ in each occurrence independently is hydrogen, alkyl,        cycloalkyl, heterocyclyl, aryl or heteroaryl; and    -   R¹² and R¹³ in each occurrence independently are hydrogen,        alkyl, cycloalkyl, heterocyclyl, aryl or heteroaryl, or R¹² and        R¹³ and the nitrogen atom to which they are connected form a        heterocyclic or heteroaryl ring.

II. Stereoisomers

It is understood that the present disclosure encompasses all possiblestereoisomers, including both enantiomers and all possible diastereomersin substantially pure form and mixtures of both enantiomers in any ratio(including a racemic mixture of enantiomers) and mixtures of two or morediastereomers in any ratio, of the adamantyl compounds described hereinhaving one or more stereocenters, and not only the specificstereoisomers as indicated by drawn structure or nomenclature, Someembodiments of the disclosure relate to the specific stereoisomersindicated by drawn structure or nomenclature. The specific recitation ofthe phrase “or stereoisomers thereof” or the like with respect to acompound in certain instances of the disclosure shall not be interpretedas an intended omission of any of the other possible stereoisomers ofthe compound in other instances of the disclosure where the term“compound” is used without recitation of the phrase “or stereoisomersthereof” or the like, unless the context clearly indicates otherwise.

III. Aminoadamantyl Nitrate Compounds

The present disclosure provides novel aminoadamantyl nitrate compounds.In some embodiments, the compounds are of Formula I:

wherein:

-   -   R¹ and R² independently are hydrogen, halide, linear or branched        alkyl, linear or branched heteroalkyl, linear or branched        alkoxy, linear or branched —O-heteroalkyl, cycloalkyl,        heterocyclyl, aryl or heteroaryl, each of which can optionally        be substituted;    -   R³ and R⁴ independently are hydrogen or linear or branched C₁-C₆        alkyl, or R³, R⁴ and the nitrogen atom to which they are        attached form a 3-8-membered heterocyclic ring;    -   R⁵ is hydrogen or linear or branched C₁-C₆ alkyl;    -   X is bond, linear or branched -alkyl-, linear or branched        -heteroalkyl-, linear or branched —O-alkyl-, linear or branched        —O-heteroalkyl-, —(CH₂)_(j)-cycloalkyl-(CH₂)_(k)—,        —(CH₂)_(j)-heterocyclyl-(CH₂)_(k)—,        —(CH₂)_(j)-aryl-(O)_(h)—(CH₂)_(k)— or        —(CH₂)_(j)-heteroaryl-(O)_(h)—(CH₂)_(k)—, each of which can        optionally be substituted;    -   Y is —ONO₂ or

-   -   m is 0, 1, 2, 3, 4 or 5;    -   j is 0, 1, 2 or 3;    -   k is 0, 1, 2 or 3; and    -   h is 0 or 1;        and pharmaceutically acceptable salts, solvates, hydrates,        clathrates, polymorphs and stereoisomers thereof.

In certain embodiments, the compounds are of Formula Ia:

wherein:

-   -   R¹, R², X and Y are as defined for Formula I; and    -   n is 1, 2, 3, 4, 5 or 6;        and pharmaceutically acceptable salts, solvates, hydrates,        clathrates, polymorphs and stereoisomers thereof.

In some embodiments, the compounds are of Formula IA:

-   -   wherein R¹, R², R³, R⁴, R⁵, X and m are as defined for Formula        I;        and pharmaceutically acceptable salts, solvates, hydrates,        clathrates, polymorphs and stereoisomers thereof.

In certain embodiments, the compounds are of Formula IAa:

wherein:

-   -   R¹, R² and X are as defined for Formula I; and    -   n is 1, 2, 3, 4, 5 or 6;        and pharmaceutically acceptable salts, solvates, hydrates,        clathrates, polymorphs and stereoisomers thereof.

In further embodiments, the compounds are of Formula IB:

-   -   wherein R¹, R², R³, R⁴, R⁵, X and m are as defined for Formula        I;        and pharmaceutically acceptable salts, solvates, hydrates,        clathrates, polymorphs and stereoisomers thereof. The        stereocenter of the vicinal dinitrate moiety can have the R- or        S-stereochemistry or can be racemic.

In certain embodiments, the compounds are of Formula IBa:

wherein:

-   -   R¹, R² and X are as defined for Formula I; and    -   n is 1, 2, 3, 4, 5 or 6;        and pharmaceutically acceptable salts, solvates, hydrates,        clathrates, polymorphs and stereoisomers thereof. The        stereocenter of the vicinal dinitrate moiety can have the R- or        S-stereochemistry or can be racemic.

In some embodiments, X of the compounds of Formula I and subgenusesthereof is bond, linear or branched C₁-C₆ or C₁-C₃-alkyl-, or linear orbranched C₁-C₆ or C₁-C₃—O-alkyl-. In certain embodiments, X of thecompounds of Formula I and subgenuses thereof is bond or linear orbranched C₁-C₃-alkyl- [e.g., —CH₂—, —(CH₂)₂—, —CHCH₃, —(CH₂)₃—,—CHCH₂CH₃, —CH₂CHCH₃ or —CH(CH₃)CH₂—].

In other embodiments, aminoadamantyl nitrate compounds are of Formula IIand Formula III:

wherein:

-   -   R¹ and R² independently are hydrogen, halide, linear or branched        alkyl, linear or branched heteroalkyl, linear or branched        alkoxy, linear or branched —O-heteroalkyl, cycloalkyl,        heterocyclyl, aryl or heteroaryl, each of which can optionally        be substituted;    -   R³ and R⁴ independently are hydrogen or linear or branched C₁-C₆        alkyl, or R³, R⁴ and the nitrogen atom to which they are        attached form a 3-8-membered heterocyclic ring;    -   R⁵ is hydrogen or linear or branched C₁-C₆ alkyl;    -   X is bond, linear or branched -alkyl-, linear or branched        -heteroalkyl-, linear or branched —O-alkyl-, linear or branched        —O-heteroalkyl-, —(CH₂)_(j)-cycloalkyl-(CH₂)_(k)—,        —(CH₂)_(j)-heterocyclyl-(CH₂)_(k)—,        —(CH₂)_(j)-aryl-(O)_(h)—(CH₂)_(k)— or        —(CH₂)_(j)-heteroaryl-(O)_(h)—(CH₂)_(k)—, each of which can        optionally be substituted;    -   Y is —ONO₂ or

-   -   m is 0, 1, 2, 3, 4 or 5;    -   j is 0, 1, 2 or 3;    -   k is 0, 1, 2 or 3; and    -   h is 0 or 1;        and pharmaceutically acceptable salts, solvates, hydrates,        clathrates, polymorphs and stereoisomers thereof.

In some embodiments, the compounds are of Formula IV:

wherein:

-   -   R¹, R², X and Y are as defined for Formulas II and III; and    -   p is 0, 1, 2, 3, 4, 5 or 6;        and pharmaceutically acceptable salts, solvates, hydrates,        clathrates, polymorphs and stereoisomers thereof.

In certain embodiments, the compounds are of Formula IVa:

wherein:

-   -   X and Y are as defined for Formulas II and III; and    -   p is 0, 1, 2, 3, 4, 5 or 6;        and pharmaceutically acceptable salts, solvates, hydrates,        clathrates, polymorphs and stereoisomers thereof.

In further embodiments, the compounds are of Formula IIA and FormulaIIIA:

-   -   wherein R¹, R², R³, R⁴, R⁵, X and m are as defined for Formulas        TT and 111;        and pharmaceutically acceptable salts, solvates, hydrates,        clathrates, polymorphs and stereoisomers thereof.

In some embodiments, the compounds are of Formula IVA:

wherein:

-   -   R¹, R² and X are as defined for Formulas II and III; and    -   p is 0, 1, 2, 3, 4, 5 or 6;        and pharmaceutically acceptable salts, solvates, hydrates,        clathrates, polymorphs and stereoisomers thereof.

In certain embodiments, the compounds are of Formula IVAa:

wherein:

-   -   X is as defined for Formulas II and TII; and    -   p is 0, 1, 2, 3, 4, 5 or 6;        and pharmaceutically acceptable salts, solvates, hydrates,        clathrates, polymorphs and stereoisomers thereof.

In additional embodiments, the compounds are of Formula IIB and FormulaIIIB:

-   -   wherein R¹, R², R³, R⁴, R⁵, X and m are as defined for Formulas        II and III;        and pharmaceutically acceptable salts, solvates, hydrates,        clathrates, polymorphs and stereoisomers thereof. The        stereocenter of the vicinal dinitrate moiety can have the R- or        S-stereochemistry or can be racemic.

In some embodiments, the compounds are of Formula IVB:

wherein:

-   -   R¹, R² and X are as defined for Formulas II and III; and    -   p is 0, 1, 2, 3, 4, 5 or 6;        and pharmaceutically acceptable salts, solvates, hydrates,        clathrates, polymorphs and stereoisomers thereof. The        stereocenter of the vicinal dinitrate moiety can have the R- or        S-stereochemistry or can be racemic.

In certain embodiments, the compounds are of Formula IVBa:

wherein:

-   -   X is as defined for Formulas II and III; and    -   p is 0, 1, 2, 3, 4, 5 or 6;        and pharmaceutically acceptable salts, solvates, hydrates,        clathrates, polymorphs and stereoisomers thereof. The        stereocenter of the vicinal dinitrate moiety can have the R- or        S-stereochemistry or can be racemic.

For the compounds of Formula TT and subgenuses thereof, the compounds ofFormula III and subgenuses thereof, and the compounds of Formula IV andsubgenuses thereof, the X—Y, X—ONO₂ or —X—CH(ONO₂)CH₂—ONO₂ moiety can beattached to an ortho position, a meta position or the para position ofthe phenyl ring. In certain embodiments, the —X—Y, —X—ONO₂ or—X—CH(ONO₂)CH₂—ONO₂ moiety is attached to a meta position of the phenylring.

For the compounds of Formula II and subgenuses thereof, the compounds ofFormula III and subgenuses thereof, and the compounds of Formula IV andsubgenuses thereof, in some embodiments X is bond, linear or branchedC₁-C₆ or C₁-C₃-alkyl-, or linear or branched C₁-C₆ or C₁-C₃—O-alkyl-. Incertain embodiments, X is bond or linear or branched C₁-C₃—O-alkyl-[e.g., —O—CH₂—, —O—(CH₂)₂—, —O—CHCH₃, —O—(CH₂)₃—, —O—CHCH₂CH₃,—O—CH₂CHCH₃ or —O—CH(CH₃)CH₂—].

Regarding the compounds of Formula I and subgenuses thereof, thecompounds of Formula II and subgenuses thereof, and the compounds ofFormula III and subgenuses thereof, examples of 3-8-membered,nitrogen-containing heterocyclic rings include without limitationaziridinyl, azetidinyl, pyrrolidinyl, piperidinyl, azepanyl andazocanyl. In certain embodiments, R³, R⁴ and the nitrogen atom to whichthey are attached form a 3-6-membered heterocyclic ring.

For the compounds of Formula I and subgenuses thereof, the compounds ofFormula III and subgenuses thereof, and the compounds of Formula IV andsubgenuses thereof, in certain embodiments m is 0, 1 or 2; n is 1, 2 or3; and p is 0, 1, 2 or 3.

There may be a steric effect in the (electrostatic) interaction of theamine group of the aminoadamantyl nitrate compounds (which is protonatedat physiological pH) at or near the N+1 site of the GluN2 (or NR2)subunit in the channel selectivity filter region of the NMDAR channel.For the compounds of Formula I and subgenuses thereof, the compounds ofFormula II and subgenuses thereof, and the compounds of Formula III andsubgenuses thereof, in some embodiments both R³ and R⁴ are hydrogen. Inother embodiments, one of R³ and R⁴ is hydrogen, and the other is linearor branched C₁-C₃ alkyl. In certain embodiments, one of R³ and R⁴ ishydrogen, and the other is methyl or ethyl. In yet other embodiments, R³and R⁴ independently are linear C₁-C₃ alkyl (e.g., methyl or ethyl),optionally the same alkyl group.

For the compounds of Formula I and subgenuses thereof and the compoundsof Formula III and subgenuses thereof, in some embodiments R⁵ ishydrogen. In other embodiments, R⁵ is linear or branched C₁-C₃ alkyl. Incertain embodiments, R⁵ is methyl or ethyl. If the carbon atom connectedto the amine group is a stereocenter, the stereocenter can have the R-or S-stereochemistry or can be racemic.

For the compounds of Formula I and subgenuses thereof, the compounds ofFormula II and subgenuses thereof, the compounds of Formula III andsubgenuses thereof, and the compounds of Formula IV and subgenusesthereof, in some embodiments R¹ and R² independently are hydrogen orlinear or branched C₁-C₆ or C₁-C₃ alkyl. In certain embodiments, both R¹and R² are hydrogen. In other embodiments, R¹ is hydrogen and R² islinear or branched C₁-C₆ or C₁-C₃ alkyl, or R² is hydrogen and R¹ islinear or branched C₁-C₆ or C₁-C₃ alkyl. In certain embodiments, R¹ ishydrogen and R² is methyl, ethyl or n-propyl, or R² is hydrogen and R¹is methyl, ethyl or n-propyl. In yet other embodiments, R¹ and R²independently are linear or branched C₁-C₆ or C₁-C₃ alkyl, optionallythe same alkyl group. In certain embodiments, R¹ and R² independentlyare methyl, ethyl or n-propyl, optionally the same alkyl group. In someembodiments, R¹ is hydrogen and R² is ethyl, or R² is hydrogen and R¹ isethyl. In other embodiments, both R¹ and R² are ethyl.

A non-hydrogen group (e.g., an alkyl group) for R¹ or/and R² canincrease a compound's binding affinity for and dwell time in, and slowits off rate from, the open ion channel of activated NMDA receptors.Furthermore, a more hydrophobic group (e.g., a longer alkyl group) forR¹, R² or/and X can increase binding affinity, can compensate for loweraffinity that may be associated with the presence of a non-hydrogengroup at C-3, C-5 and C-7 of the adamantane scaffold, and can increase acompound's affinity and selectivity for extrasynaptic NMDARs oversynaptic NMDARs, although the degree of hydrophobicity of a compound orgroup(s) thereof may need to be balanced with its solubility in aqueoussolution.

For the compounds of Formula I and subgenuses thereof, the compounds ofFormula II and subgenuses thereof, the compounds of Formula III andsubgenuses thereof, and the compounds of Formula IV and subgenusesthereof, in some embodiments the R¹ group, the R² group or the X group,or any combination or all thereof, independently are substituted with 1,2 or 3 substituents selected from linear or branched C₁-C₆ or C₁-C₃alkyl, haloalkyl, —OR⁶, —NR⁷R⁸, —ONO₂, —CN, —C(═O)R⁶, —C(═O)OR⁶,—OC(═O)R⁶, —C(═O)NR⁷R⁸, —NR⁷C(═O)R⁶, —OC(═O)OR⁶, —OC(═O)NR⁷R⁸,—NR⁷C(═O)OR⁶, —NR⁶C(═O)NR⁷R⁸, aryl and heteroaryl, or/and aresubstituted with 1 to 6 halogen (e.g., fluorine) or deuterium atoms orhave all available hydrogen atoms replaced with halogen (e.g., fluorine)or deuterium atoms, wherein:

-   -   R⁶ in each occurrence independently is hydrogen or linear or        branched C₁-C₆ or C₁-C₃ alkyl; and    -   R⁷ and R⁸ in each occurrence independently are hydrogen or        linear or branched C₁-C₆ or C₁-C₃ alkyl, or R⁷, R⁸ and the        nitrogen atom to which they are attached form a 3-6-membered        ring.        In certain embodiments, the R¹ group, the R² group or the X        group, or any combination or all thereof, independently are        monovalent or divalent deuteroalkyl, fluoroalkyl or alkyl-ONO₂.

Regarding the compounds of Formula I and subgenuses thereof, thecompounds of Formula II and subgenuses thereof, the compounds of FormulaIII and subgenuses thereof, and the compounds of Formula IV andsubgenuses thereof, non-limiting examples of linear or branched C₁-C₆alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl,isobutyl, sec-butyl, tert-butyl, n-pentyl and n-hexyl. Examples oflinear or branched C₁-C₃ alkyl groups include methyl, ethyl, n-propyland isopropyl.

For the compounds of Formula I and subgenuses thereof, the compounds ofFormula II and subgenuses thereof, the compounds of Formula III andsubgenuses thereof, and the compounds of Formula IV and subgenusesthereof, in some embodiments X has 0, 1, 2, 3, 4, 5 or 6 carbon atoms.In certain embodiments, X has 0, 1, 2 or 3 carbon atoms.

Table 1 shows representative compounds of Formula IAa:

TABLE 1 For each subgenus IAa-i, IAa-ii, IAa-iii, IAa-iv, IAa-v, IAa-vi,IAa- vii, IAa-viii, IAa-ix, IAa-x, IAa-xi, IAa-xii, IAa-xiii, IAa-xiv,IAa-xv, IAa-xvi, IAa-xvii, IAa-viii, IAa-xix and IAa-xx n R¹ R² 1, 2 and3 methyl methyl 1, 2 and 3 hydrogen methyl 1, 2 and 3 methyl hydrogen 1,2 and 3 ethyl ethyl 1, 2 and 3 hydrogen ethyl 1, 2 and 3 ethyl hydrogen1, 2 and 3 n-propyl n-propyl 1, 2 and 3 hydrogen n-propyl 1, 2 and 3n-propyl hydrogen 1, 2 and 3 isopropyl isopropyl 1, 2 and 3 hydrogenisopropyl 1, 2 and 3 isopropyl hydrogen 1, 2 and 3 n-butyl n-butyl 1, 2and 3 hydrogen n-butyl 1, 2 and 3 n-butyl hydrogen 1, 2 and 3 isobutylisobutyl 1, 2 and 3 hydrogen isobutyl 1, 2 and 3 isobutyl hydrogen 1, 2and 3 sec-butyl sec-butyl 1, 2 and 3 hydrogen sec-butyl 1, 2 and 3sec-butyl hydrogen 1, 2 and 3 —CH₂—ONO₂ —CH₂—ONO₂ 1, 2 and 3 hydrogen—CH₂—ONO₂ 1, 2 and 3 —CH₂—ONO₂ hydrogen 1, 2 and 3 —(CH₂)₂—ONO₂—(CH₂)₂—ONO₂ 1, 2 and 3 hydrogen —(CH₂)₂—ONO₂ 1, 2 and 3 —(CH₂)₂—ONO₂hydrogen 1, 2 and 3 —(CH₂)₃—ONO₂ —(CH₂)₃—ONO₂ 1, 2 and 3 hydrogen—(CH₂)₃—ONO₂ 1, 2 and 3 —(CH₂)₃—ONO₂ hydrogen 1, 2 and 3 —CH₂CH(ONO₂)CH₃—CH₂CH(ONO₂)CH₃ 1, 2 and 3 hydrogen —CH₂CH(ONO₂)CH₃ 1, 2 and 3—CH₂CH(ONO₂)CH₃ hydrogen 1, 2 and 3 —CH₂CH(CH₃)CH₂—ONO₂—CH₂CH(CH₃)CH₂—ONO₂ 1, 2 and 3 hydrogen —CH₂CH(CH₃)CH₂—ONO₂ 1, 2 and 3—CH₂CH(CH₃)CH₂—ONO₂ hydrogenand pharmaceutically acceptable salts, solvates, hydrates, clathrates,polymorphs and stereoisomers thereof. The present disclosurespecifically discloses each of the 2160 compounds shown in Table 1 andeach of the possible stereoisomers thereof. An alkyl-ONO₂ group with astereocenter can have the R- or S-stereochemistry or can be racemic atthat stereocenter. Likewise, an R¹ or R² group with a stereocenter canhave the R- or S-stereochemistry or can be racemic at that stereocenter.

In certain embodiments, the compounds of Formula IAa are selected from:

and pharmaceutically acceptable salts, solvates, hydrates, clathrates,polymorphs and stereoisomers thereof, wherein Et=ethyl and Pr=n-propyl.An alkyl-ONO₂ group with a stereocenter can have the R- orS-stereochemistry or can be racemic at that stereocenter.

Table 2 shows representative compounds of Formula IBa:

TABLE 2 For each subgenus IBa-i, IBa-ii, IBa-iii, IBa-iv, IBa-v, IBa-vi,IBa-vii and IBa-viii n R¹ R² 1, 2 and 3 methyl methyl 1, 2 and 3hydrogen methyl 1, 2 and 3 methyl hydrogen 1, 2 and 3 ethyl ethyl 1, 2and 3 hydrogen ethyl 1, 2 and 3 ethyl hydrogen 1, 2 and 3 n-propyln-propyl 1, 2 and 3 hydrogen n-propyl 1, 2 and 3 n-propyl hydrogen 1, 2and 3 isopropyl isopropyl 1, 2 and 3 hydrogen isopropyl 1, 2 and 3isopropyl hydrogen 1, 2 and 3 n-butyl n-butyl 1, 2 and 3 hydrogenn-butyl 1, 2 and 3 n-butyl hydrogen 1, 2 and 3 isobutyl isobutyl 1, 2and 3 hydrogen isobutyl 1, 2 and 3 isobutyl hydrogen 1, 2 and 3sec-butyl sec-butyl 1, 2 and 3 hydrogen sec-butyl 1, 2 and 3 sec-butylhydrogen 1, 2 and 3 —CH₂—ONO₂ —CH₂—ONO₂ 1, 2 and 3 hydrogen —CH₂—ONO₂ 1,2 and 3 —CH2—ONO₂ hydrogen 1, 2 and 3 —(CH₂)₂—ONO₂ —(CH₂)₂—ONO₂ 1, 2 and3 hydrogen —(CH₂)₂—ONO₂ 1, 2 and 3 —(CH₂)₂—ONO₂ hydrogen 1, 2 and 3—(CH₂)₃—ONO₂ —(CH₂)₃—ONO₂ 1, 2 and 3 hydrogen —(CH₂)₃—ONO₂ 1, 2 and 3—(CH₂)₃—ONO₂ hydrogen 1, 2 and 3 —CH₂CH(ONO₂)CH₃ —CH₂CH(ONO₂)CH₃ 1, 2and 3 hydrogen —CH₂CH(ONO₂)CH₃ 1, 2 and 3 —CH₂CH(ONO₂)CH₃ hydrogen 1, 2and 3 —CH₂CH(CH₃)CH₂—ONO₂ —CH₂CH(CH₃)CH₂—ONO₂ 1, 2 and 3 hydrogen—CH₂CH(CH₃)CH₂—ONO₂ 1, 2 and 3 —CH₂CH(CH₃)CH₂—ONO₂ hydrogenand pharmaceutically acceptable salts, solvates, hydrates, clathrates,polymorphs and stereoisomers thereof. The present disclosurespecifically discloses each of the 864 compounds shown in Table 2 andeach of the possible stereoisomers thereof. A nitrated alkyl group witha stereocenter at a branch point can have the R- or S-stereochemistry orcan be racemic at that stereocenter. The stereocenter of the vicinaldinitrate moiety can have the R- or S-stereochemistry or can be racemic.Moreover, an R¹ or R² group with a stereocenter can have the R- orS-stereochemistry or can be racemic at that stereocenter.

In certain embodiments, the compounds of Formula IBa are selected from:

and pharmaceutically acceptable salts, solvates, hydrates, clathrates,polymorphs and stereoisomers thereof, wherein Et=ethyl and Pr=n-propyl.A nitrated alkyl group with a stereocenter at a branch point can havethe R- or S-stereochemistry or can be racemic at that stereocenter.Likewise, the stereocenter of the vicinal dinitrate moiety can have theR- or S-stereochemistry or can be racemic.

Table 3 shows representative compounds of Formula IVA:

TABLE 3 For each subgenus IVA-i, IVA-ii, IVA-iii, IVA-iv, IVA-v, IVA-viand IVA-vii p R¹ R² 0, 1, 2 and 3 hydrogen hydrogen 0, 1, 2 and 3 methylmethyl 0, 1, 2 and 3 hydrogen methyl 0, 1, 2 and 3 methyl hydrogen 0, 1,2 and 3 ethyl ethyl 0, 1, 2 and 3 hydrogen ethyl 0, 1, 2 and 3 ethylhydrogen 0, 1, 2 and 3 n-propyl n-propyl 0, 1, 2 and 3 hydrogen n-propyl0, 1, 2 and 3 n-propyl hydrogen 0, 1, 2 and 3 isopropyl isopropyl 0, 1,2 and 3 hydrogen isopropyl 0, 1, 2 and 3 isopropyl hydrogen 0, 1, 2 and3 n-butyl n-butyl 0, 1, 2 and 3 hydrogen n-butyl 0, 1, 2 and 3 n-butylhydrogen 0, 1, 2 and 3 isobutyl isobutyl 0, 1, 2 and 3 hydrogen isobutyl0, 1, 2 and 3 isobutyl hydrogen 0, 1, 2 and 3 sec-butyl sec-butyl 0, 1,2 and 3 hydrogen sec-butyl 0, 1, 2 and 3 sec-butyl hydrogen 0, 1, 2 and3 —CH₂—ONO₂ —CH₂—ONO₂ 0, 1, 2 and 3 hydrogen —CH₂—ONO₂ 0, 1, 2 and 3—CH₂—ONO₂ hydrogen 0, 1, 2 and 3 —(CH₂)₂—ONO₂ —(CH₂)₂—ONO₂ 0, 1, 2 and 3hydrogen —(CH₂)₂—ONO₂ 0, 1, 2 and 3 —(CH₂)₂—ONO₂ hydrogen 0, 1, 2 and 3—(CH₂)₃—ONO₂ —(CH₂)₃—ONO₂ 0, 1, 2 and 3 hydrogen —(CH₂)₃—ONO₂ 0, 1, 2and 3 —(CH₂)₃—ONO₂ hydrogen 0, 1, 2 and 3 —CH₂CH(ONO₂)CH₃—CH₂CH(ONO₂)CH₃ 0, 1, 2 and 3 hydrogen —CH₂CH(ONO₂)CH₃ 0, 1, 2 and 3—CH₂CH(ONO₂)CH₃ hydrogen 0, 1, 2 and 3 —CH₂CH(CH₃)CH₂—ONO₂—CH₂CH(CH₃)CH₂—ONO₂ 0, 1, 2 and 3 hydrogen —CH₂CH(CH₃)CH₂—ONO₂ 0, 1, 2and 3 —CH₂CH(CH₃)CH₂—ONO₂ hydrogenand pharmaceutically acceptable salts, solvates, hydrates, clathrates,polymorphs and stereoisomers thereof. The present disclosurespecifically discloses each of the 1036 compounds shown in Table 3 andeach of the possible stereoisomers thereof. An R¹ or R² group with astereocenter can have the R- or S-stereochemistry or can be racemic atthat stereocenter.

In certain embodiments, the compounds of Formula IVA are selected from:

and pharmaceutically acceptable salts, solvates, hydrates, clathrates,polymorphs and stereoisomers thereof.

Table 4 shows representative compounds of Formula IVB:

TABLE 4 For each subgenus IVB-i, IVB-ii, IVB-iii, IVB-iv, IVB-v andIVB-vi p R¹ R² 0, 1, 2 and 3 hydrogen hydrogen 0, 1, 2 and 3 methylmethyl 0, 1, 2 and 3 hydrogen methyl 0, 1, 2 and 3 methyl hydrogen 0, 1,2 and 3 ethyl ethyl 0, 1, 2 and 3 hydrogen ethyl 0, 1, 2 and 3 ethylhydrogen 0, 1, 2 and 3 n-propyl n-propyl 0, 1, 2 and 3 hydrogen n-propyl0, 1, 2 and 3 n-propyl hydrogen 0, 1, 2 and 3 isopropyl isopropyl 0, 1,2 and 3 hydrogen isopropyl 0, 1, 2 and 3 isopropyl hydrogen 0, 1, 2 and3 n-butyl n-butyl 0, 1, 2 and 3 hydrogen n-butyl 0, 1, 2 and 3 n-butylhydrogen 0, 1, 2 and 3 isobutyl isobutyl 0, 1, 2 and 3 hydrogen isobutyl0, 1, 2 and 3 isobutyl hydrogen 0, 1, 2 and 3 sec-butyl sec-butyl 0, 1,2 and 3 hydrogen sec-butyl 0, 1, 2 and 3 sec-butyl hydrogen 0, 1, 2 and3 —CH₂—ONO₂ —CH₂—ONO₂ 0, 1, 2 and 3 hydrogen —CH₂—ONO₂ 0, 1, 2 and 3—CH₂—ONO₂ hydrogen 0, 1, 2 and 3 —(CH₂)₂—ONO₂ —(CH₂)₂—ONO₂ 0, 1, 2 and 3hydrogen —(CH₂)₂—ONO₂ 0, 1, 2 and 3 —(CH₂)₂—ONO₂ hydrogen 0, 1, 2 and 3—(CH₂)₃—ONO₂ —(CH₂)₃—ONO₂ 0, 1, 2 and 3 hydrogen —(CH₂)₃—ONO₂ 0, 1, 2and 3 —(CH₂)₃—ONO₂ hydrogen 0, 1, 2 and 3 —CH₂CH(ONO₂)CH₃—CH₂CH(ONO₂)CH₃ 0, 1, 2 and 3 hydrogen —CH₂CH(ONO₂)CH₃ 0, 1, 2 and 3—CH₂CH(ONO₂)CH₃ hydrogen 0, 1, 2 and 3 —CH₂CH(CH₃)CH₂—ONO₂—CH₂CH(CH₃)CH₂—ONO₂ 0, 1, 2 and 3 hydrogen —CH₂CH(CH₃)CH₂—ONO₂ 0, 1, 2and 3 —CH₂CH(CH₃)CH₂—ONO₂ hydrogenand pharmaceutically acceptable salts, solvates, hydrates, clathrates,polymorphs and stereoisomers thereof. The present disclosurespecifically discloses each of the 888 compounds shown in Table 4 andeach of the possible stereoisomers thereof. The stereocenter of thevicinal dinitrate moiety can have the R- or S-stereochemistry or can beracemic. Likewise, an R¹ or R² group with a stereocenter can have the R-or S-stereochemistry or can be racemic at that stereocenter.

In certain embodiments, the compounds of Formula IVB are selected from:

and pharmaceutically acceptable salts, solvates, hydrates, clathrates,polymorphs and stereoisomers thereof. The stereocenter of the vicinaldinitrate moiety can have the R- or S-stereochemistry or can be racemic.

Instead of being an amine group, the amine group indirectly or directlyconnected to the C-1 position of the aminoadamantyl nitrate compoundsdescribed herein can be an amide, carbamate or urea. The amine group ofaminoadamantyl compounds, which is protonated at physiological pH, bindsto the memantine/phencyclidine-binding site at or near the Mg²⁺-bindingsite of open NMDAR channels by hydrogen bonding, with the protonatedamine group acting as a hydrogen-bond donor and the side chain ofasparagine at position 616 of the GluN1 (or NR1) subunit acting as ahydrogen-bond acceptor, as well as by electrostatic interaction withasparagine residues of the GluN2 (or NR2) subunit. An —NH(C═O)R amide,—NH(C═O)OR carbamate or —NHC(═O)NR^(a)R^(b) urea group can also act as ahydrogen-bond donor. In some embodiments, the —NR³R⁴ moiety ofaminoadamantyl nitrate compounds is —NH(C═O)R⁶, —NH(C═O)OR⁶ or—NHC(═O)NR⁷R⁸, wherein R⁶ is hydrogen (for formamide) or linear orbranched C₁-C₆ alkyl, and R⁷ and R⁸ independently are hydrogen or linearor branched C₁-C₆ alkyl, or R⁷, R⁸ and the nitrogen atom to which theyare attached form a 3-6-membered ring. In certain embodiments, R⁶ ishydrogen (for formamide) or linear or branched C₁-C₃ alkyl (e.g., methylor ethyl), and R⁷ and R⁸ independently are hydrogen or linear orbranched C₁-C₃ alkyl (e.g., methyl or ethyl).

IV. Salt Forms

The adamantyl compounds described herein have one or more amine groups(possibly unless the amine group indirectly or directly connected to theC-1 position of the adamantyl scaffold is an amide, carbamate or urea)and can exist as a free base or as salts. They can be used oradministered as a free base or as pharmaceutically acceptable salts. Anamine group can form an addition salt with an acid, such as a mineralacid (e.g., HCl, HBr, HI, nitric acid, phosphoric acid or sulfuric acid)or an organic acid (e.g., a carboxylic acid or a sulfonic acid).Suitable acids for use in the preparation of pharmaceutically acceptablesalts include without limitation acetic acid, 2,2-dichloroacetic acid,acylated amino acids, adipic acid, alginic acid, ascorbic acid,L-aspartic acid, benzenesulfonic acid, benzoic acid, 4-acetamidobenzoicacid, boric acid, (+)-camphoric acid, camphorsulfonic acid, (+)-(1S)-camphor-10-sulfonic acid, capric acid, caproic acid, caprylic acid,cinnamic acid, citric acid, cyclamic acid, cyclohexanesulfamic acid,dodecylsulfuric acid, ethane-1,2-disulfonic acid, ethanesulfonic acid,2-hydroxyethanesulfonic acid, formic acid, fumaric acid, galactaricacid, gentisic acid, glucoheptonic acid, D-gluconic acid, D-glucuronicacid, L-glutamic acid, alpha-oxo-glutaric acid, glycolic acid, hippuricacid, hydrobromic acid, hydrochloric acid, hydroiodic acid,(±)-DL-lactic acid, (+)-L-lactic acid, lactobionic acid, lauric acid,maleic acid, (−)-L-malic acid, malonic acid, (±)-DL-mandelic acid,methanesulfonic acid, naphthalene-2-sulfonic acid,naphthalene-1,5-disulfonic acid, 1-hydroxy-2-naphthoic acid, nicotinicacid, nitric acid, oleic acid, orotic acid, oxalic acid, palmitic acid,pamoic acid, perchloric acid, phosphoric acid, propionic acid,L-pyroglutamic acid, pyruvic acid, saccharic acid, salicylic acid,4-amino-salicylic acid, sebacic acid, stearic acid, succinic acid,sulfuric acid, tannic acid, (±)-DL-tartaric acid, (+)-L-tartaric acid,thiocyanic acid, p-toluenesulfonic acid, undecylenic acid, and valericacid.

If a compound has an acidic group (e.g., a carboxyl group), the acidicgroup can form an addition salt with a base. Pharmaceutically acceptablebase addition salts can be formed with, e.g., metals (e.g., alkalimetals or alkaline earth metals) or amines (e.g., organic amines).Examples of metals useful as cations include without limitation alkalimetals (e.g., lithium, sodium, potassium and cesium), alkaline earthmetals (e.g., magnesium, calcium and barium), aluminum and zinc. Metalcations can be provided by way of, e.g., inorganic bases, such ashydroxides, carbonates and hydrogen carbonates. Non-limiting examples oforganic amines useful for forming base addition salts includechloroprocaine, choline, cyclohexylamine, dibenzylamine,N,N′-dibenzylethylenediamine, dicyclohexylamine, diethanolamine,ethylenediamine, N-ethylpiperidine, histidine, isopropylamine,N-methylglucamine, procaine, pyrazine, triethylamine, trimethylamine andtromethamine. Pharmaceutically acceptable salts are discussed in detailin Handbook of Pharmaceutical Salts, Properties, Selection and Use, P.Stahl and C. Wermuth, Eds., Wiley-VCH (2011).

In some embodiments, the aminoadamantyl nitrate compounds describedherein are used or administered in the form of pharmaceuticallyacceptable salts. In certain embodiments, the aminoadamantyl nitratecompounds are used or administered as a hydrochloride (HCl) orhydrobromide (HBr) salt.

V. Isotopologues, Including Deuterated Compounds

The present disclosure encompasses all isotopically enriched forms ofthe aminoadamantyl nitrate compounds described herein, including withoutlimitation those enriched in the content of ²H (deuterium), ¹³C, ¹⁵N,¹⁷O or ¹⁸O, or any combination thereof, at one or more, or all,instances of the corresponding atom(s).

To eliminate foreign substances such as drugs, the animal body expressesa variety of enzymes, such as cytochrome P₄₅₀ enzymes, esterases,proteases, reductases, dehydrogenases and monoamine oxidases, whichreact with and convert the foreign substances to more polarintermediates or metabolites for renal excretion. Such metabolicreactions can involve the oxidation of a carbon-hydrogen (C—H) bond to acarbon-oxygen (C—O) bond or a carbon-carbon (C═C) pi bond, or acarbon-oxygen (C—O) single bond to a carbon-oxygen (C═O) double bond.The resulting metabolites may be stable or unstable under physiologicalconditions, and may have substantially different pharmacologic,pharmacokinetic and pharmacodynamic properties and toxicity profilescompared to the parent compounds. For many drugs, such metabolicoxidations can be rapid and lead to the requirement of higher dosageamounts or/and increased dosing frequencies, which can result in greaterside effects.

The disclosure provides isotopologues corresponding to theaminoadamantyl nitrate compounds described herein which are enrichedwith deuterium (deuterated) at one or more positions. Deuteration at oneor more positions can have any one or more, or all, of the followingbenefits: (1) a longer half-life; (2) decreased amount of a dose or/anddecreased number of doses needed to achieve a desired effect; (3)decreased variation between subjects in the blood or plasma level of theparent drug; (4) increased efficacy; (5) reduced side effects due todecreased amount of the parent drug administered or/and decreasedproduction of deleterious metabolites; and (6) increased maximumtolerated dose.

Deuterium can be substituted for hydrogen at any one or more, or all, ofthe available positions in an aminoadamantyl nitrate compound, includingwithout limitation at any one or more, or all, of the availablepositions in the adamantyl scaffold, the alkyl group connecting theamine group to the C-1 position of the adamantyl scaffold (unless theamine group is directly connected to the C-1 position), the X group(unless X is a bond), the R¹ group (unless R¹ is halide), the R² group(unless R² is halide), or the phenyl ring of a compound of Formula II,III or IV, or any combination thereof. In certain embodiments, anaminoadamantyl nitrate compound is deuterated at the carbon atomattached to the amine group that is indirectly connected to the C-1position of the adamantyl scaffold (unless the amine group is directlyconnected to the C-1 position), or/and is deuterated at the carbon atomattached to a nitrate group for one or more, or all, nitrate groupsdepending on whether the compound has one or more nitrate groups (unlessthe compound has only one nitrate group and X is a bond). In furtherembodiments, an aminoadamantyl nitrate is deuterated at one or more, orall, of the available positions in the R¹ group (unless R¹ is halide)or/and the R² group (unless R² is halide).

In some embodiments, at least one of the available positions in anaminoadamantyl nitrate has deuterium enrichment of at least about 10%,25%, 50%, 75%, 90%, 95% or 98%. In certain embodiments, at least one ofthe available positions has deuterium enrichment of at least about 90%,95% or 98%. In further embodiments, each position in an aminoadamantylnitrate enriched with deuterium (or deuterated) independently hasdeuterium enrichment of at least about 10%, 25%, 50%, 75%, 90%, 95% or98%. In certain embodiments, each position enriched with deuterium (ordeuterated) independently has deuterium enrichment of at least about90%, 95% or 98%.

The term “deuterium enrichment” refers to the percentage ofincorporation of deuterium at a given position in a molecule in place ofhydrogen. For example, deuterium enrichment of 10% at a given positionmeans that 10% of molecules in a given sample contain deuterium at thatposition. Because the naturally occurring distribution of deuterium isabout 0.0156%, deuterium enrichment at any position in a moleculesynthesized using non-deuterium-enriched starting materials or reagentsis about 0.0156%. Deuterium enrichment can be determined usingconventional analytical methods known to one of ordinary skill in theart, including mass spectrometry and nuclear magnetic resonancespectroscopy.

The term “is deuterium” or “is deuterated”, when used to describe agiven position in a molecule, or the symbol “D”, when used to representan element at a given position in a drawing of a molecular structure,means that the specified position is enriched with deuterium above thenaturally occurring distribution of deuterium. In some embodiments,deuterium enrichment is at least about 10%, 20%, 30%, 40%, 50%, 60%,70%, 80%, 90%, 95%, 98% or 99% (e.g., at least about 50%) of deuteriumat the specified position. In certain embodiments, deuterium enrichmentis at least about 90%, 95% or 98% of deuterium at the specifiedposition.

VI. Therapeutic Uses of Aminoadamantyl Nitrate Compounds

Overactivation of the NMDA receptor, relieving the voltage-dependentchannel block by Mg²⁺ and causing excessive influx of Ca²⁺ andsubsequent oxidative stress due to overproduction of reactive oxygenspecies, can lead to neuronal excitotoxicity and ultimately neuronalinjury and death. Without intending to be bound by theory, it isbelieved that stimulation of extrasynaptic NMDA receptors (eNMDAR)rather than synaptic NMDA receptors (sNMDAR) is responsible forexcitotoxicity implicated in neurodegenerative disorders. Synaptic NMDARactivity is phasic by nature and synaptic NMDARs generally aretransiently and intensely activated by trans-synaptic release ofglutamate. By contrast, extrasynaptic NMDARs typically are activatedchronically by elevated levels of ambient glutamate, whether resultingfrom synaptic release of glutamate or/and impairment or reversal ofuptake of glutamate [G. Hardingham et al., Nat. Rev. Neurosci.,11:682-696 (2010)]. Because synaptic NMDARs typically arephasically/transiently activated while extrasynaptic NMDARs typicallyare chronically/tonically activated, it is primarily extrasynapticNMDARs that are excessively activated and hence allow an excessive andprolonged influx of Ca²⁺ through the excessively/persistently open ionchannel. Furthermore, under conditions of chronic NMDAR activation suchas excessive levels of glutamate or NMDA, synaptic NMDAR activity issuppressed and extrasynaptic NMDAR signaling pathways dominate [F.Soriano et al., J Neurosci., 26:4509-4518 (2006)].

Synaptic NMDAR activity promotes cell health and survival, whereasextrasynaptic NMDAR activity initiates cell-death pathways andantagonizes synaptic NMDAR-induced cell-survival pathways. Ca²⁺ influxevoked by intense activation of synaptic NMDARs causes no perturbationto mitochondrial membrane potential and enhances mitochondrial health,and triggers genomic processes primarily via nuclear Ca²⁺ signaling thatrender neurons more resistant to oxidative stress and apoptosis(including decreased expression of pro-apoptotic factors such ascaspases). An episode of synaptic NMDAR activity promotes “acquired”neuroprotection that lasts after most signaling pathways are no longeractive. In contrast, comparable intracellular Ca²⁺ concentrationsinduced by activation of extrasynaptic NMDARs—either on their own or inthe presence of activation of synaptic NMDARs—trigger nitochondrialdysfunction (including loss of mitochondrial membrane potential) andcell death (whether by apoptosis or necrosis). Mitochondrialdysfunction, activation of the intrinsic mitochondrial apoptoticpathway, and oxidative stress due to overproduction of reactive oxygenspecies are implicated in the pathogenesis of neurodegenerativediseases. The stark differences in the outcome from activation ofsynaptic NMDARs and extrasynaptic NMDARs result from opposing effects onintracellular signaling pathways, many involving the same signalproteins, and induction of very different programs of gene expression.Nuclear Ca²⁺, an important regulator of gene expression, plays a keyrole in the pro-survival effects of synaptic NMDAR activation and isdisrupted by extrasynaptic NMDAR activity. Many neurodegenerativedisorders and other CNS disorders share common signaling pathwaysdownstream of extrasynaptic NMDAR activity which contribute toneurotoxicity. See, e.g., Hardingham (2010, supra) and M. Parsons etal., Neuron, 82:279-293 (2014).

Activation of extrasynaptic NMDA receptors rather than synaptic NMDAreceptors is believed to be responsible for excitotoxicity implicated inneurodegenerative disorders such as Alzheimer's disease, Huntington'sdisease, Parkinson's disease and amyotrophic lateral sclerosis, and inother CNS disorders such as epilepsy, stroke and traumatic brain injury[Hardingham (2010, supra) and Parsons (2014, supra)]. ExtrasynapticNMDAR expression or/and activation are elevated in disease states[Parsons (2014, supra)]. In a study relating to Alzheimer's disease(AD), the amyloid-_(β1-42) peptide stimulates the α-7 nicotinicacetylcholine receptor and hence the release of an excessive amount ofglutamate from astrocytes, which in turn activates neuronalextrasynaptic NMDARs that mediate nitric oxide production, tauhyperphosphorylation, caspase-3 activation and mitochondrialdysfunction, resulting in neuronal spine loss and loss of synapsesassociated with cognitive decline in AD [M. Talantova et al., Proc. Nat.Acad. Sci. USA, 110:E2518-E2527 (2013)]. Loss of synapses can cause animbalance of synaptic NMDAR and extrasynaptic NMDAR activity andsignaling that can lead to cell death associated with neurodegenerativediseases such as Alzheimer's disease and Huntington's disease.

In addition to the location of NMDARs, the subunit composition of NMDARsmay play an important role in the biological activity of NMDARs. NMDARsassemble as heterotetramers having two obligatory GluN1 subunits and twoGluN2 (GluN2A, 2B, 2C or 2D) or/and GluN3 (GluN3A or 3B) subunits. Thelarge majority of NMDARs in the CNS assemble as a GluN1/GluN2A orGluN1/GluN2B diheteromer, or as a GluN1/GluN2A/GluN2B triheteromer.Although both subtypes can be found synaptically and extrasynaptically,the GluN2A (or NR2A) subtype is enriched in synaptic NMDARs, while theGluN2B (or NR2B) subtype is more prevalent in extrasynaptic NMDARs [L.Groc et al., Proc. Natl. Acad. Sci. USA, 103:18769-18774 (2006); and M.Martel et al., Neurosci., 158:334-343 (2009)]. GluN2A-containing NMDARsare associated with cell survival, whereas GluN2B-containing NMDARs arelinked to cell death [T. Lai et al., Trends Mol. Med., 17:266-275(2011)]. Furthermore, intracellular signaling via the GluN2B C-terminaldomain is a large contributor to NMDA-induced excitotoxicity [M. Martelet al., Neuron, 74:543-556 (2012)].

Neurodegenerative and other CNS disorders associated with excitotoxicevents can be treated through blockade of extrasynaptic NMDARs. Thephysiological activity of synaptic NMDARs is essential for normalneuronal function, so an NMDAR antagonist needs to block activatedextrasynaptic NMDARs without suppressing the normal activity of synapticNMDARs. This can be achieved by an uncompetitive antagonist, or openchannel blocker, that selectively enters the opened channel ofextrasynaptic NMDARs after they have been activated by the binding ofco-agonists and thereby blocks the flow of cations, in particular Ca²⁺.

The aminoadamantyl nitrate compounds described herein act asvoltage-dependent, uncompetitive antagonists that selectively blockextrasynaptic NMDARs. They have a relatively low affinity for, and arelatively fast off rate from, the memantine/phencyclidine-binding siteat or near the Mg²⁺-binding site in the channel of activated NMDARs sothat they do not accumulate in the channel when it closes and hencepreserve the physiological activity of phasically activated synapticNMDARs and avoid psychiatric side effects associated with high-affinityNMDAR antagonists [S. Lipton, Curr. Drug Targets, 8:621-632 (2007)].However, the aminoadamantyl nitrate compounds have a sufficiently highaffinity (e.g., a KI from about 200 nM to about single-digit μM) for thememantine/phencyclidine-binding site and a sufficiently long dwell timein the excessively/persistently open ion channel of tonically activatedextrasynaptic NMDARs so that they block excessive influx of Ca²⁺ throughthe channel and thereby prevent excitotoxic events. Whether administeredas an acid addition salt or a free base, the amine group of theadamantyl compounds is protonated at physiological pH (pH of about 7.4).The protonated amine group binds at or near the Mg²⁺-binding site in thechannel of activated NMDARs with a higher affinity, a sloweroff/dissociation rate and lesser voltage dependence than Mg²⁺ does atthe Mg²⁺-binding site, allowing the adamantyl compounds to blockprolonged influx of Ca²⁺ through the channel. The protonated amine groupforms a hydrogen bond with the side chain of asparagine at position 616of the GluN1 (or NR1) subunit at the narrowest constriction of the pore(the channel selectivity filter), and also has significant electrostaticinteraction with the carbonyl oxygen atom of the side chain ofasparagine residues at the N and N+1 sites of the GluN2 (or NR2) subunitthere [H.-S. Chen et al., J. Pharmacol. Exper. Therap., 314:961-971(2005)]. The Mg²⁺-binding site is within the electric field of thechannel, so blockade of the channel by a (positively) charged agentbinding at or near the Mg²⁺-binding site is voltage-dependent.

Increased binding affinity of the aminoadamantyl nitrate compounds forextrasynaptic NMDARs is also provided by hydrophobic interaction betweenthe compounds and the subunits of extrasynaptic NMDARs. The two methylgroups of memantine engage in hydrophobic interaction with hydrophobicbinding pockets formed by the residues A645 and A644 in the thirdtransmembrane helix of the GluN1 (or NR1) subunit and the GluN2B (orNR2B) subunit, respectively, which greatly increases memantine's bindingaffinity for activated NMDARs compared to that of amantadine [W.Limapichat et al., ACS Chem. Neurosci., 4:255-260 (2013)]. The GluN2B(or NR2B) subtype is more prevalent in extrasynaptic NMDARs.Aminoadamantyl nitrate compounds having a non-hydrogen (e.g., alkyl)group for R¹ and R² can engage in hydrophobic interaction with thehydrophobic binding pockets of the GluN1 and GluN2B subunits ofextrasynaptic NMDARs. The R¹ group is believed to be oriented toward thehydrophobic binding pocket of GluN2B. A greater number of carbon atomsof a group increases its hydrophobicity/lipophilicity.

The aminoadamantyl nitrate compounds described herein selectivelyinhibit activated extrasynaptic NMDARs and possess a dual mechanism ofinhibition. They block the open ion channel of activated extrasynapticNMDARs in a voltage-dependent manner by binding at or near theMg²⁺-binding site in the channel, and they suppress the activity ofactivated extrasynaptic NMDARs in a voltage-independent manner byS-nitrosylation of cysteine residues of a redox modulatory site on thereceptor. The ion-channel conductivity of NMDA receptors is regulated bynitrosylation [Y. Choi et al., Nat. Neurosci., 3:15-21 (2000)]. Bindingof the protonated amine group of an aminoadamantyl nitrate at or nearthe Mg²⁺-binding site in the open ion channel of activated extrasynapticNMDARs brings a nitrate group of the compound in close proximity tocysteine residues of a redox modulatory site in the extracellular domainof the receptor. Oxidation at the redox site, possibly resulting in theformation of one or more disulfide bonds involving two or more cysteineresidues, downregulates/desensitizes NMDAR channel activity. The nitrategroup of the aminoadamantyl compound donates/transfers NO (e.g., in theform of NO⁺) to a cysteine residue of the redox site, possibly with theaid of glutathione S-transferase. If the aminoadamantyl compound has twoor more nitrate groups, two or more nitrate groups can potentiallytransfer NO to two or more of about five cysteine residues of the redoxsite. S-nitrosylation of cysteine residue(s) oxidizes the sulfhydrylgroup of the cysteine residue(s), or may facilitate the formation ofdisulfide bond(s). The effect of S-nitrosylation of cysteine residue(s)of the redox site is suppression of the activity of, and Ca²⁺ influxthrough, extrasynaptic NMDAR channels. In neurons, nitric oxide synthase(NOS) is activated by the influx of Ca²⁺ through NMDAR channels,resulting in nitric oxide (NO) production. NO downregulates NOS andinhibits Ca²⁺ influx through NMDAR channels via negative feedback.Targeting of the NO-donating nitrate group(s) of the aminoadamantylcompound to the cysteine residues of the redox site avoids potentialvascular and neurotoxic side effects of free nitric oxide, such asvasodilation, apoptosis and formation of neurotoxic peroxynitrite. Afterdonation of NO for S-nitrosylation, the resulting protonatedaminoadamantyl compound with a hydroxyl group in place of each donornitrate group remains bound at or near the Mg²⁺-binding site, unless itsvoltage-gated blockade of the ion channel is attenuated by membranedepolarization. However, the redox modulatory site is outside of thevoltage field of the channel, and hence suppression of the channelactivity of activated extrasynaptic NMDARs by S-nitrosylation ofcysteine residues of the redox site is voltage-independent and remainsfor a significant amount of time after the compound is expelled from thechannel by depolarization. Inhibition of activated extrasynaptic NMDARsvia S-nitrosylation of cysteine residues markedly increases underhypoxic condition, and thus is particularly suited for, but not limitedto, preventing or reducing neuronal damage due to cerebral ischemia suchas stroke and vasular dementia [H. Takahashi et al., Sci. Rep., 5:14781(2015)].

The aminoadamantyl nitrate compounds described herein selectivelyinhibit activated extrasynaptic NMDARs and thereby prevent or curtailexcitotoxicity while sparing normal synaptic NMDAR activity. Sparing theNMDAR component of excitatory postsynaptic currents (EPSCs) isneurotrophic and avoids synaptic injury. Like nitromemantine, theaminoadamantyl nitrate compounds described herein have at least onenitrate group. Memantine preferentially blocks the excessively openchannel of activated extrasynaptic NMDARs while relatively sparingnormal synaptic NMDAR activity, even under conditions of pathologicaldepolarization in the presence of extracellular Mg²⁺[P. Xia et al., J.Neurosci., 30:11246-11250 (2010)]. Nitromemantine inhibits extrasynapticNMDAR activity more selectively and spares synaptic NMDAR activity to agreater degree than memantine [Takahashi (2015, supra)]. Selectiveinhibition of extrasynaptic NMDARs results in greater neuroprotectionand less side effects than uncompetitive antagonists that block bothsynaptic NMDARs and extrasynaptic NMDARs (e.g., high-affinity NMDARantagonists) or are less selective for the latter (e.g., memantine). Theaminoadamantyl nitrate compounds described herein can prevent or reduceloss of synapses and death of neurons, increase synaptic and dendriticdensity, and enhance the cognitive function of Alzheimer's patients byantagonizing extrasynaptic NMDARs as well as the α-7 nicotinicacetylcholine receptor with, e.g., chronic treatment. Furthermore, theaminoadamantyl nitrate compounds can stimulate regrowth of synapses andrestore lost synapses with, e.g., prolonged administration.

In addition, the aminoadamantyl nitrate compounds described herein canpromote long-term potentiation (LTP) underlying synaptic plasticity andhence memory and learning. Synaptic plasticity is the ability ofchemical synapses to change their strength, and permits regulatedstrengthening or weakening of specific connections in an organizedfashion. Memories are believed to be encoded by modification of synapticstrength. LTP is a persistent strengthening of synapses based on recentpatterns of synaptic activity that produce a long-lasting increase insignal transmission between two neurons, a process believed to encodeand store learning and long-term memory. The opposite of LTP islong-term depression (LTD), which produces a long-lasting decrease insynaptic strength. Activation of synaptic NMDA receptors induces LTP,and their inhibition impairs LTP [Parsons (2014, supra)]. In contrast,activation of extrasynaptic NMDA receptors inhibit LTP and induce LTD[Li et al., J. Neurosci., 31:6627-6638 (2011); and Liu et al., BrainRes. Bull., 93:10-16 (2013)]. By selectively antagonizing activatedextrasynaptic NMDARs while not interfering with physiological synapticNMDAR activity, the aminoadamantyl nitrate compounds can promote orspare LTP and prevent or curtail LTD, and thereby can restore synapticplasticity and enhance cognitive function. Moreover, the compounds canaid recovery of synaptic function and thereby improve impaired memoryand learning.

Many neurodegenerative disorders and other CNS disorders share commonsignaling pathways downstream of extrasynaptic NMDAR activity whichcontribute to neuronal dysfunction, damage and death. As selectiveuncompetitive antagonists of activated extrasynaptic NMDARs, theaminoadamantyl nitrate compounds described herein can be used to treat awide variety of neurodegenerative disorders and other CNS disorders.Non-limiting examples of neurodegenerative disorders that can be treatedwith the aminoadamantyl nitrate compounds described herein includedementia (e.g., Alzheimer's disease, vascular dementia, dementia withLewy bodies, frontotemporal dementia and HIV-associated dementia),Huntington's disease (which often leads to dementia), Parkinson'sdisease (which often leads to dementia), multiple system atrophy(Shy-Drager syndrome), cerebellar degeneration, ataxia (e.g., cerebellarataxia, spinocerebellar ataxia, Friedreich's ataxia andataxia-telangiectasia [Louis-Bar syndrome]), motor neuron diseases(e.g., amyotrophic lateral sclerosis [ALS], primary lateral sclerosis[PLS], progressive muscular atrophy [PMA] and spinal muscular atrophy[SMA]), multiple sclerosis, vision impairment or loss caused byneurodegeneration of the visual pathway (e.g., optic neuropathy/atrophy,glaucoma and age-related macular degeneration [AMD]), and sensorineuralhearing loss. See, e.g., Hardingham (2010, supra); Parsons (2014,supra); A. Kritis et al., Front. Cell. Neurosci., 9:91 (2015); A. Iizukaet al., Neurosci. Lett., 592:37-41 (2015); S. Rossi et al., PLOS One,8:e67357-e67369 (2013); N. Osborne et al., Br. J. Ophthalmol.,83:980-986 (1999); and V. Kotak et al., J. Neurosci., 25:3908-3918(2005).

In certain embodiments, the aminoadamantyl nitrate compounds describedherein are used to treat a neurodegenerative disorder selected fromAlzheimer's disease, vascular dementia, Huntington's disease,Parkinson's disease and ALS.

Examples of other CNS disorders, which may or may not involveneurodegeneration in their pathophysiology, that can be treated with theaminoadamantyl nitrate compounds described herein include withoutlimitation cerebrovascular disorders (including brain ischemia[including acute ischemia such as stroke, chronic ischemia such asvascular dementia, cerebral ischemia/reperfusion injury, andneurological damage caused by low oxygen or/and glucose levels in thebrain], intracerebral hemorrhage and retinopathy), brain injury andtrauma (including traumatic brain injury, diffuse axonal injury, primaryand secondary brain injury, focal and diffuse brain injury, anoxic andhypoxic brain injury, intracerebral hemorrhage and brain edema), spinalcord injury (due to, e.g., trauma, ischemia or a degenerative disorder),epilepsy (including neurological damage caused by epileptic seizures),dyskinesia (e.g., levodopa-induced dyskinesia and tardive dyskinesia),spasticity, pain (e.g., acute pain, chronic pain, allodynia, complexregional pain syndrome [CRPS], fibromyalgia, hyperalgesia, inflammatorypain, neuropathic pain, postoperative pain, cancer-related pain,drug-induced pain and injury-induced pain), headaches (including primaryheadaches [e.g., migraine, cluster headache and tension headache] andsecondary headaches [due to, e.g., a cerebrovascular disorder, a brainbleed, a brain injury, a brain infection or a brain tumor),neurodevelopmental disorders (including MEF2C haploinsufficiencysyndrome [MCHS], autism spectrum disorder [including autism],developmental delay, intellectual disability, fragile X syndrome,attention-deficit hyperactivity disorder [ADHD] and schizophrenia), mooddisorders (including depressive disorders [e.g., major depressivedisorder and treatment-resistant depression], bipolar disorders anddementia-related mood disorders), and anxiety disorders (includinggeneralized anxiety disorder, stress disorders [e.g., acute stressdisorder, post-traumatic stress disorder and chronic stress], andobsessive-compulsive disorder). See, e.g., Hardingham (2010); Parsons(2014); S. Ivanova et al., Parkinsons Dis., 2016:6461907 (2016); C.Woolf, Pain, 152:S2-15 (2011); M. Zhuo, Neuropharmacol., 112:228-234(2017); X. Moisset et al., Headache, 57:1261-1264 (2017); L. Huang etal., Ann. Pharmacother., 48:1507-1511 (2014); C. Hu et al., J.Pharmacol. Sci., 132:115-121 (2016); D. Rossignol et al., Front.Pediatrics, 2:87 (2014); S. Tu et al., Nat. Commun., 8:1488 (2017); A.Toft et al., J Neurosci., 36:9817-9827 (2016); M. Ghasemi et al.,Neurosci. Biobehav. Rev., 80:555-572 (2017); E. Lang et al., Neurosci.Biobehav. Rev., S0149-7634:30322-30326 (2017); C. Kraus et al., Int. J.Psychiatry Clin. Pract., 21:2-12 (2017); T. Schwartz et al., Case Rep.Psychiatry, 2012:749796 (2012); and N. Li et al., Biol. Psychiatry,69:754-761 (2011).

In certain embodiments, the aminoadamantyl nitrate compounds describedherein are used to treat a CNS disorder selected from brain ischemia,traumatic brain injury, epilepsy, pain and autism spectrum disorder.

The therapeutically effective amount and the frequency of administrationof an aminoadamantyl nitrate compound to treat a neurodegenerative orother CNS disorder may depend on various factors, including the type ofdisorder, the severity of the condition, the potency of the compound,the mode of administration, the age, body weight, general health, genderand diet of the subject, and the response of the subject to thetreatment, and can be determined by the treating physician. In someembodiments, the effective dose of an aminoadamantyl nitrate per day isfrom about 1, 5 or 10 mg to about 100 mg, or as deemed appropriate bythe treating physician, which can be administered in a single dose or individed doses. In certain embodiments, the effective dose of anaminoadamantyl nitrate per day is from about 5 or 10 mg to about 50 mg,or about 50-100 mg. In further embodiments, the effective dose of anaminoadamantyl nitrate per day is about 1, 5, 10, 15, 20, 25, 30, 40,50, 60, 70, 80, 90 or 100 mg. In certain embodiments, the effective doseof an aminoadamantyl nitrate per day is about 10-30 mg, or about 10, 15,20, 25 or 30 mg.

The dosage of an aminoadamantyl nitrate can be adjusted during thecourse of the treatment regimen, which can be determined by the treatingphysician. For example, an aminoadamantyl nitrate compound can beadminstered in an initial daily dose for the first week of treatment,and then the daily dose of the compound can be gradually or step-wiseincreased for every subsequent week of treatment until a target orsuitable daily maintenance dose is administered for, e.g., the fourthweek of treatment and thereafter for the duration of treatment.Increasing the dose of a drug gradually or step-wise during the initialphase of treatment would allow the treating physician to determine theoptimum therapeutic dose while avoiding or minimizing any potential sideeffect, for example. The initial doses and the maintenance dose can beany effective dose described herein. As another example, if it isdesired to establish a therapeutic level of an aminoadamantyl nitratecompound quickly for the treatment of a CNS disorder, such as a stroke,a traumatic brain injury or pain, a first loading dose of the compoundcan be administered on, e.g., day 1, an optional second loading dose canbe administered on, e.g., day 2, an optional third loading dose can beadministered on, e.g., day 3, and a maintenance dose of the compound canbe administered daily thereafter for the duration of treatment. Aloading dose can be, e.g., about 5, 4, 3, 2.5, 2 or 1.5 times largerthan the maintenance dose, and the optional second and third loadingdoses can be, e.g., smaller than the previous loading dose. Themaintenance dose can be any effective dose described herein.

An aminoadamantyl nitrate can be administered in any suitable frequencyto treat a neurodegenerative or other CNS disorder, which can bedetermined by the treating physician. In some embodiments, anaminoadamantyl nitrate is administered daily (including one, two or moretimes daily), every two days, every three days or weekly, or as deemedappropriate by the treating physician. In certain embodiments, anaminoadamantyl nitrate is administered once daily.

An aminoadamantyl nitrate can be administered for any suitable period oftime to treat a neurodegenerative or other CNS disorder, which can bedetermined by the treating physician. For the treatment of aneurodegenerative disorder, in some embodiments an aminoadamantylnitrate is administered for a period of at least about 3 months, 6months, 1 year, 1.5 years, 2 years, 3 years, 4 years, 5 years or longer.For the treatment of a CNS disorder that may or may not involveneurodegeneration in its pathophysiology, in certain embodiments anaminoadamantyl nitrate is administered for a period of at least about 1week, 2 weeks, 1 month, 2 months, 3 months, 6 months, 1 year, 1.5 years,2 years, 3 years or longer.

An aminoadamantyl nitrate can also be administered pro re nata (asneeded) for the treatment of a CNS disorder, which can be determined bythe treating physician. For example, for the treatment of pain orheadache an aminoadamantyl nitrate can be taken until the pain orheadache dissipates. If pain or headache returns, administration of theaminoadamantyl nitrate can be resumed. The appropriate dosage of, thefrequency of dosing of and the length of treatment with anaminoadamantyl nitrate for a neurodegenerative or other CNS disorder canbe determined by the treating physician.

A aminoadamantyl nitrate can be administered via any suitable route, andcan be administered locally or systemically, for the treatment of aneurodegenerative or other CNS disorder, which can be determined by thetreating physician. Potential routes of administration of anaminoadamantyl nitrate include without limitation oral, parenteral(including intradermal, subcutaneous, intramuscular, intravascular,intravenous, intraarterial, intraperitoneal, intramedullary, intrathecaland topical), intracavitary, and topical (including dermal/epicutaneous,transdermal, mucosal, transmucosal, intranasal [e.g., by nasal spray ordrop], intraocular [e.g., by eye drop], pulmonary [e.g., by oral ornasal inhalation], buccal, sublingual, rectal [e.g., by suppository],and vaginal [e.g., by suppository]). In certain embodiments, anaminoadamantyl nitrate is administered orally (e.g., as a tablet orcapsule). In other embodiments, an aminoadamantyl nitrate isadministered parenterally (e.g., intravenously, intramuscularly orsubcutaneously, whether by injection or infusion).

The aminoadamantyl nitrate compounds described herein can effectivelycross the blood-brain barrier (BBB) for the treatment ofneurodegenerative and other CNS disorders, or the blood-retinal barrier(BRB) for the treatment of eye disorders such as glaucoma, AMD andretinopathy. They are small molecules with a hydrophobic/lipophilicscaffold and hence can penetrate into the brain or the eye. Increasingthe lipophilicity of group(s) on aminoadamantyl compounds increasestheir ability to cross the BBB or the BRB. For example, 7 days ofinfusion of memantine or amantadine (20 and 100 mg/kg/day, respectively)resulted in a whole brain concentration of memantine or amantadine thatwas 44-fold and 16-fold higher than free concentration in serum,respectively [M. Hesselink et al., Pharm. Res., 16:637-642 (1999)].

An aminoadamantyl nitrate can optionally be used in combination with oneor more additional therapeutic agents to treat a neurodegenerative orother CNS disorder.

VII. Pharmaceutical Compositions

Additional embodiments of the disclosure relate to pharmaceuticalcompositions comprising an aminoadamantyl nitrate compound describedherein, or a pharmaceutically acceptable salt, solvate, hydrate,clathrate or polymorph thereof, and one or more pharmaceuticallyacceptable excipients or carriers. The compositions can optionallycontain an additional therapeutic agent. A pharmaceutical compositioncontains a therapeutically effective amount of an aminoadamantylnitrate, one or more pharmaceutically acceptable excipients or carriersand optionally a therapeutically effective amount of an additionaltherapeutic agent, and is formulated for administration to a subject fortherapeutic use.

A pharmaceutical composition contains an aminoadamantyl nitrate andoptionally an additional therapeutic agent in substantially pure form.In some embodiments, the purity of the aminoadamantyl nitrate and theoptional additional therapeutic agent independently is at least about95%, 96%, 97%, 98% or 99%. In certain embodiments, the purity of theaminoadamantyl nitrate and the optional additional therapeutic agentindependently is at least about 98% or 99%. In addition, apharmaceutical composition is substantially free of contaminants orimpurities. In some embodiments, the level of contaminants or impuritiesother than residual solvent in a pharmaceutical composition is no morethan about 5%, 4%, 3%, 2% or 10% relative to the combined weight of theintended active and inactive ingredients. In certain embodiments, thelevel of contaminants or impurities other than residual solvent in apharmaceutical composition is no more than about 2% or 1% relative tothe combined weight of the intended active and inactive ingredients.Pharmaceutical compositions generally are prepared according to currentgood manufacturing practice (GMP), as recommended or required by, e.g.,the Federal Food, Drug, and Cosmetic Act § 501(a)(2)(B) and theInternational Conference on Harmonisation Q7 Guideline.

Pharmaceutical compositions/formulations can be prepared in sterileform. For example, pharmaceutical compositions/formulations forparenteral administration by injection or infusion generally aresterile. Sterile pharmaceutical compositions/formulations are compoundedor manufactured according to pharmaceutical-grade sterilizationstandards known to those of skill in the art, such as those disclosed inor required by the United States Pharmacopeia Chapters 797, 1072 and1211, and 21 Code of Federal Regulations 211.

Pharmaceutically acceptable excipients and carriers includepharmaceutically acceptable substances, materials and vehicles.Non-limiting examples of excipients include liquid and solid fillers,diluents, binders, lubricants, glidants, surfactants, dispersing agents,disintegration agents, emulsifying agents, wetting agents, suspendingagents, thickeners, solvents, isotonic agents, buffers, pH adjusters,absorption-delaying agents, stabilizers, preservatives, antioxidants,antimicrobial agents, antibacterial agents, antifungal agents,adjuvants, sweetening agents, flavoring agents, coloring agents,encapsulating materials and coating materials. The use of suchexcipients in pharmaceutical formulations is known in the art. Forexample, conventional vehicles and carriers include without limitationoils (e.g., vegetable oils, such as sesame oil), aqueous solvents (e.g.,saline, phosphate-buffered saline [PBS] and isotonic solutions [e.g.,Ringer's solution]), and solvents (e.g., dimethyl sulfoxide [DMSO] andalcohols [e.g., ethanol, glycerol and propylene glycol]). Except insofaras any conventional excipient or carrier is incompatible with the activeingredient, the disclosure encompasses the use of conventionalexcipients and carriers in formulations containing aminoadamantylnitrate compounds. See, e.g., Remington: The Science and Practice ofPharmacy, 21st Ed., Lippincott Williams & Wilkins (Philadelphia, Pa.[2005]); Handbook of Pharmaceutical Excipients, 5th Ed., Rowe et al.,Eds., The Pharmaceutical Press and the American PharmaceuticalAssociation (2005); Handbook of Pharmaceutical Additives, 3rd Ed., Ashand Ash, Eds., Gower Publishing Co. (2007); and PharmaceuticalPre-formulation and Formulation, Gibson, Ed., CRC Press LLC (Boca Raton,Fla. [2004]).

Proper formulation can depend on various factors, such as the route ofadministration chosen. Potential routes of administration ofpharmaceutical compositions comprising aminoadamantyl nitrate compoundsinclude without limitation oral, parenteral (including intradermal,subcutaneous, intramuscular, intravascular, intravenous, intraarterial,intraperitoneal, intramedullary, intrathecal and topical),intracavitary, and topical (including dermal/epicutaneous, transdermal,mucosal, transmucosal, intranasal [e.g., by nasal spray or drop],intraocular [e.g., by eye drop], pulmonary [e.g., by oral or nasalinhalation], buccal, sublingual, rectal [e.g., by suppository], andvaginal [e.g., by suppository]). Topical formulations can be designed toproduce a local or systemic therapeutic effect.

As an example, formulations of aminoadamantyl nitrate compounds suitablefor oral administration can be presented as, e.g., boluses; capsules(including push-fit capsules and soft capsules), tablets, pills, cachetsor lozenges; as powders or granules; as semisolids, electuaries, pastesor gels; as solutions or suspensions in an aqueous liquid or/and anon-aqueous liquid; or as oil-in-water liquid emulsions or water-in-oilliquid emulsions.

Push-fit capsules or two-piece hard gelatin capsules can contain anaminoadamantyl nitrate in admixture with, e.g., a filler or inert soliddiluent (e.g., calcium carbonate, calcium phosphate, kaolin or lactose),a binder (e.g., a starch), a glidant or lubricant (e.g., talc ormagnesium stearate), and a disintegrant (e.g., crospovidone), andoptionally a stabilizer or/and a preservative. For soft capsules orsingle-piece gelatin capsules, an aminoadamantyl nitrate can bedissolved or suspended in a suitable liquid (e.g., liquid polyethyleneglycol or an oil medium, such as a fatty oil, peanut oil, olive oil orliquid paraffin), and the liquid-filled capsules can contain one or moreother liquid excipients or/and semi-solid excipients, such as astabilizer or/and an amphiphilic agent (e.g., a fatty acid ester ofglycerol, propylene glycol or sorbitol). In certain embodiments, acapsule (e.g., a hard gelatin capsule) comprises an aminoadamantylnitrate and sugar spheres, polyvinylpyrrolidone, hypromellose, talc,polyethylene glycol, ethylcellulose, ammonium hydroxide, oleic acid, andmedium-chain triglycerides.

Tablets can contain an aminoadamantyl nitrate in admixture with, e.g., afiller or inert diluent (e.g., calcium carbonate, calcium phosphate,lactose, mannitol or microcrystalline cellulose), a binding agent (e.g.,a starch, gelatin, acacia, alginic acid or a salt thereof, ormicrocrystalline cellulose), a lubricating agent (e.g., stearic acid,magnesium stearate, talc or silicon dioxide), and a disintegrating agent(e.g., crospovidone, croscarmellose sodium or colloidal silica), andoptionally a surfactant (e.g., sodium lauryl sulfate). The tablets canbe uncoated or can be coated with, e.g., an enteric coating thatprotects the active ingredient from the acidic environment of thestomach, or with a material that delays disintegration and absorption ofthe active ingredient in the gastrointestinal tract and thereby providesa sustained action over a longer time period. In certain embodiments, atablet comprises an aminoadamantyl nitrate and lactose monohydrate,microcrystalline cellulose, silica colloidal anhydrous, talc andmagnesium stearate, and is film-coated (e.g., a film-coating containinghypromellose, titanium dioxide and macrogol 400).

Compositions for oral administration can also be formulated as solutionsor suspensions in an aqueous liquid or/and a non-aqueous liquid, or asoil-in-water liquid emulsions or water-in-oil liquid emulsions.Dispersible powder or granules of an aminoadamantyl nitrate can be mixedwith any suitable combination of an aqueous liquid, an organic solventor/and an oil and any suitable excipients (e.g., any combination of adispersing agent, a wetting agent, a suspending agent, an emulsifyingagent or/and a preservative) to form a solution, suspension or emulsion.

Aminoadamantyl nitrate compounds can also be formulated for parenteraladministration by injection or infusion to circumvent gastrointestinalabsorption and first-pass metabolism. An exemplary parenteral route isintravenous. Additional advantages of intravenous administration includedirect administration of a therapeutic agent into systemic circulationto achieve a rapid systemic effect, and the ability to administer theagent continuously or/and in a large volume if desired. Formulations forinjection or infusion can be in the form of, e.g., solutions,suspensions or emulsions in oily or aqueous vehicles, and can containexcipients such as suspending agents, dispersing agents or/andstabilizing agents. For example, aqueous or non-aqueous (e.g., oily)sterile injection solutions can contain an aminoadamantyl nitrate alongwith excipients such as an antioxidant, a buffer, a bacteriostat andsolutes that render the formulation isotonic with the blood of thesubject. Aqueous or non-aqueous sterile suspensions can contain anaminoadamantyl nitrate along with excipients such as a suspending agentand a thickening agent, and optionally a stabilizer and an agent thatincreases the solubility of the aminoadamantyl nitrate to allow for thepreparation of a more concentrated solution or suspension. As anotherexample, a sterile aqueous solution for injection or infusion (e.g.,subcutaneously or intravenously) can contain an aminoadamantyl nitrate,sodium chloride, a buffering agent (e.g., sodium citrate), apreservative (e.g., meta-cresol), and optionally a base (e.g., NaOH)or/and an acid (e.g., HCl) to adjust pH.

For topical administration, an aminoadamantyl nitrate can be formulatedas, e.g., a buccal or sublingual tablet or pill. Advantages of a buccalor sublingual tablet or pill include avoidance of gastrointestinalabsorption and first-pass metabolism, and rapid absorption into systemiccirculation. A buccal or sublingual tablet or pill can be designed toprovide faster release of the aminoadamantyl nitrate for more rapiduptake of it into systemic circulation. In addition to a therapeuticallyeffective amount of an aminoadamantyl nitrate, the buccal or sublingualtablet or pill can contain suitable excipients, including withoutlimitation any combination of fillers and diluents (e.g., mannitol andsorbitol), binding agents (e.g., sodium carbonate), wetting agents(e.g., sodium carbonate), disintegrants (e.g., crospovidone andcroscarmellose sodium), lubricants (e.g., silicon dioxide [includingcolloidal silicon dioxide] and sodium stearyl fumarate), stabilizers(e.g., sodium bicarbonate), flavoring agents (e.g., spearmint flavor),sweetening agents (e.g., sucralose), and coloring agents (e.g., yellowiron oxide).

For topical administration, aminoadamantyl nitrate compounds can also beformulated for intranasal administration. The nasal mucosa provides abig surface area, a porous endothelium, a highly vascular subepitheliallayer and a high absorption rate, and hence allows for highbioavailability. Moreover, intranasal administration avoids first-passmetabolism and can introduce a significant concentration of theaminoadamantyl nitrate to the CNS. An intranasal formulation cancomprise an aminoadamantyl nitrate along with excipients, such as asolubility enhancer (e.g., propylene glycol), a humectant (e.g.,mannitol or sorbitol), a buffer and water, and optionally a preservative(e.g., benzalkonium chloride), a mucoadhesive agent (e.g.,hydroxyethylcellulose) or/and a penetration enhancer.

An additional mode of topical administration of an aminoadamantylnitrate is pulmonary, including by oral inhalation and nasal inhalation.The lungs serve as a portal to the systemic circulation. Advantages ofpulmonary drug delivery include, for example: 1) avoidance of first passhepatic metabolism; 2) fast drug action; 3) large surface area of thealveolar region for absorption, high permeability of the lungs (thinair-blood barrier), and profuse vasculature of the airways; 4) reducedextracellular enzyme levels compared to the gastronintestinal tract dueto the large alveolar surface area; and 5) smaller doses to achieveequivalent therapeutic effect compared to other oral routes, and hencereduced systemic side effects. An advantage of oral inhalation overnasal inhalation includes deeper penetration/deposition of the drug intothe lungs. Oral or nasal inhalation can be achieved by means of, e.g., ametered-dose inhaler, a dry powder inhaler or a nebulizer, as is knownin the art. In certain embodiments, a sterile aqueous solution for oralinhalation contains an aminoadamantyl nitrate, sodium chloride, abuffering agent (e.g., sodium citrate), optionally a preservative (e.g.,meta-cresol), and optionally a base (e.g., NaOH) or/and an acid (e.g.,HCl) to adjust pH.

Topical formulations for application to the skin or mucosa can be usefulfor transdermal or transmucosal administration of a therapeutic agentinto the blood for systemic distribution. Advantages of topicaladministration can include circumvention of gastrointestinal absorptionand first-pass metabolism, delivery of a therapeutic agent with a shorthalf-life and low oral bioavailability, more controlled and sustainedrelease of the therapeutic agent, a more uniform plasma dosing ordelivery profile of the therapeutic agent, less frequent dosing of thetherapeutic agent, minimal or no invasiveness, ease ofself-administration, and increased patient compliance.

In general, compositions suitable for topical administration includewithout limitation liquid or semi-liquid preparations such as sprays,gels, liniments, lotions, oil-in-water or water-in-oil emulsions such ascreams, foams, ointments and pastes, and solutions or suspensions suchas drops (e.g., eye drops, nose drops and ear drops). In someembodiments, a topical composition comprises an aminoadamantyl nitratedissolved, dispersed or suspended in a carrier. The carrier can be inthe form of, e.g., a solution, a suspension, an emulsion, an ointment ora gel base, and can contain, e.g., petrolatum, lanolin, a wax (e.g., beewax), mineral oil, a long-chain alcohol, polyethylene glycol orpolypropylene glycol, a diluent (e.g., water or/and an alcohol [e.g.,ethanol or propylene glycol]), a gel, an emulsifier, a thickening agent,a stabilizer or a preservative, or any combination thereof. A topicalcomposition can include, or a topical formulation can be administered bymeans of, e.g., a transdermal or transmucosal delivery device, such as atransdermal patch, a microneedle patch or an iontophoresis device. Atopical composition can deliver an aminoadamantyl nitrate transdermallyor transmucosally via a concentration gradient (with or without the useof a chemical permeation enhancer) or an active mechanism (e.g.,iontophoresis or microneedles).

For transdermal administration, in some embodiments a topicalcomposition (e.g., a transdermal delivery system) comprises a chemicalpermeation enhancer (e.g., a surfactant [e.g., sodium laureth sulfate],optionally in combination with an aromatic compound [e.g.,phenylpiperazine]) that facilitates the transport of an aminoadamantylnitrate across the skin into systemic circulation. In furtherembodiments, an aminoadamantyl nitrate is administered via a transdermalpatch. In certain embodiments, a transdermal patch comprises animpermeable backing membrane or layer, a drug reservoir, asemi-permeable membrane that can serve as a rate-limiting orrate-controlling diffusion barrier, and a skin-contacting adhesivelayer. The semi-permeable membrane can be composed of, e.g., a suitablepolymeric material (e.g., cellulose nitrate or acetate, polyisobutene,polypropylene, polyvinyl acetate or a polycarbonate). Transdermaldrug-delivery systems, including patches, can be designed to providecontrolled and prolonged release of a drug over a period of about 1week, 2 weeks, 1 month or longer.

In some embodiments, an aminoadamantyl nitrate is delivered from asustained-release composition. As used herein, the term“sustained-release composition” encompasses sustained-release,prolonged-release, extended-release, slow-release and controlled-releasecompositions, systems and devices. Use of a sustained-releasecomposition can have benefits, such as an improved profile of the amountof the drug delivered to the target site(s) over a time period,including delivery of a therapeutically effective amount of the drugover a prolonged time period. In certain embodiments, thesustained-release composition delivers the aminoadamantyl nitrate over aperiod of at least about 1 day, 2 days, 3 days, 1 week, 2 weeks, 3weeks, 1 month, 2 months, 3 months or longer. In some embodiments, thesustained-release composition is a drug-encapsulation system, such as,e.g., nanoparticles, microparticles or a capsule made of, e.g., abiodegradable polymer or/and a hydrogel. In certain embodiments, thesustained-release composition comprises a hydrogel. Non-limitingexamples of polymers of which a hydrogel can be composed includepolyvinyl alcohol, acrylate polymers (e.g., sodium polyacrylate), andother homopolymers and copolymers having a large number of hydrophilicgroups (e.g., hydroxyl or/and carboxylate groups). In other embodiments,the sustained-release drug-encapsulation system comprises amembrane-enclosed reservoir, wherein the reservoir contains a drug andthe membrane is permeable to the drug. Such a drug-delivery system canbe in the form of, e.g., a transdermal patch.

In some embodiments, the sustained-release composition is an oral dosageform, such as a tablet or capsule. For example, a drug can be embeddedin an insoluble porous matrix such that the dissolving drug must makeits way out of the matrix before it can be absorbed through thegastrointestinal tract. Alternatively, a drug can be embedded in amatrix that swells to form a gel through which the drug exits. Sustainedrelease can also be achieved by way of a single-layer or mylti-layerosmotic controlled-release oral delivery system (OROS). An OROS is atablet with a semi-permeable outer membrane and one or more smalllaser-drilled holes in it. As the tablet passes through the body, wateris absorbed through the semi-permeable membrane via osmosis, and theresulting osmotic pressure pushes the drug out through the hole(s) inthe tablet and into the gastrointestinal tract where it can be absorbed.

In further embodiments, the sustained-release composition is formulatedas polymeric nanoparticles or microparticles, wherein the polymericparticles can be delivered, e.g., by injection or from an implant. Insome embodiments, the polymeric implant or polymeric nanoparticles ormicroparticles are composed of a biodegradable polymer. In certainembodiments, the biodegradable polymer comprises lactic acid or/andglycolic acid [e.g., an L-lactic acid-based copolymer, such aspoly(L-lactide-co-glycolide) or poly(L-lacticacid-co-D,L-2-hydroxyoctanoic acid)]. The biodegradable polymer of thepolymeric implant or polymeric nanoparticles or microparticles can beselected so that the polymer substantially completely degrades aroundthe time the period of treatment is expected to end, and so that thebyproducts of the polymer's degradation, like the polymer, arebiocompatible.

For a delayed or sustained release of an aminoadamantyl nitrate, acomposition can also be formulated as, e.g., a depot that can beimplanted in or injected into a subject, e.g., intramuscularly orsubcutaneously. A depot formulation can be designed to deliver theaminoadamantyl nitrate over an extended period of time, e.g., over aperiod of at least about 1 week, 2 weeks, 3 weeks, 1 month, 6 weeks, 2months, 3 months or longer. For example, an aminoadamantyl nitrate canbe formulated with a polymeric material (e.g., polyethylene glycol[PEG], polylactic acid [PLA] or polyglycolic acid [PGA], or a copolymerthereof [e.g., PLGA]), a hydrophobic material (e.g., as an emulsion inan oil) or/and an ion-exchange resin, or as a sparingly solublederivative (e.g., a sparingly soluble salt). As an illustrative example,an aminoadamantyl nitrate can be incorporated or embedded insustained-release microparticles composed of PLGA and formulated as amonthly depot.

An aminoadamantyl nitrate compound can also be contained or dispersed ina matrix material. The matrix material can comprise a polymer (e.g.,ethylene-vinyl acetate) and controls the release of the compound bycontrolling dissolution or/and diffusion of the compound from, e.g., areservoir, and can enhance the stability of the compound while containedin the reservoir. Such a “release system” can be designed as asustained-release system, can be configured as, e.g., a transdermal ortransmucosal patch, and can contain an excipient that can accelerate thecompound's release, such as a water-swellable material (e.g., ahydrogel) that aids in expelling the compound out of the reservoir. U.S.Pat. Nos. 4,144,317 and 5,797,898 describe examples of such a releasesystem.

The release system can provide a temporally modulated release profile(e.g., pulsatile release) when time variation in plasma levels isdesired, or a more continuous or consistent release profile when aconstant plasma level is desired. Pulsatile release can be achieved froman individual reservoir or from a plurality of reservoirs. For example,where each reservoir provides a single pulse, multiple pulses(“pulsatile” release) are achieved by temporally staggering the singlepulse release from each of multiple reservoirs.

Alternatively, multiple pulses can be achieved from a single reservoirby incorporating several layers of a release system and other materialsinto a single reservoir. Continuous release can be achieved byincorporating a release system that degrades, dissolves, or allowsdiffusion of a compound through it over an extended time period. Inaddition, continuous release can be approximated by releasing severalpulses of a compound in rapid succession (“digital” release). An activerelease system can be used alone or in conjunction with a passiverelease system, as described in U.S. Pat. No. 5,797,898.

In addition, pharmaceutical compositions comprising an aminoadamantylnitrate can be formulated as, e.g., liposomes, micelles (e.g., thosecomposed of biodegradable natural or/and synthetic polymers, such aslactosomes), microparticles, microspheres or nanoparticles, whether ornot designed for sustained release.

The pharmaceutical compositions can be manufactured in any suitablemanner known in the art, e.g., by means of conventional mixing,dissolving, suspending, granulating, dragee-making, levigating,emulsifying, encapsulating, entrapping or compressing processes.

The compositions can be presented in unit dosage form as a single dosewherein all active and inactive ingredients are combined in a suitablesystem, and components do not need to be mixed to form the compositionto be administered. The unit dosage form contains an effective dose ofan aminoadamantyl nitrate. A representative example of a unit dosageform is a tablet, capsule, or pill for oral uptake.

Alternatively, the compositions can be presented as a kit, wherein theactive ingredient, excipients and carriers (e.g., solvents) are providedin two or more separate containers (e.g., ampules, vials, tubes, bottlesor syringes) and need to be combined to form the composition to beadministered. The kit can contain instructions for storing, preparingand administering the composition (e.g., a solution to be injectedintravenously).

A kit can contain all active and inactive ingredients in unit dosageform or the active ingredient and inactive ingredients in two or moreseparate containers, and can contain instructions for using thepharmaceutical composition to treat a neurodegenerative or other CNSorder. In some embodiments, a kit contains an aminoadamantyl nitrate ora pharmaceutically acceptable salt, solvate, hydrate, clathrate orpolymorph thereof, and instructions for administering the compound totreat a neurodegenerative or other CNS order.

VIII. Synthesis of Aminoadamantyl Nitrate Compounds

The synthesis of representative aminoadamantyl nitrate compounds isdescribed in the Examples and FIG. 1 .

IX. Representative Embodiments

The following embodiments of the disclosure are provided by way ofexample only:

1. A compound of Formula I:

wherein:

-   -   R¹ and R² independently are hydrogen, halide, linear or branched        alkyl, linear or branched heteroalkyl, linear or branched        alkoxy, linear or branched —O-heteroalkyl, cycloalkyl,        heterocyclyl, aryl or heteroaryl, each of which can optionally        be substituted;    -   R³ and R⁴ independently are hydrogen or linear or branched C₁-C₆        alkyl, or R³, R⁴ and the nitrogen atom to which they are        attached form a 3-8-membered heterocyclic ring;    -   R⁵ is hydrogen or linear or branched C₁-C₆ alkyl;    -   X is bond, linear or branched -alkyl-, linear or branched        -heteroalkyl-, linear or branched —O-alkyl-, linear or branched        —O-heteroalkyl-, —(CH₂)_(j)-cycloalkyl-(CH₂)_(k)—,        —(CH₂)_(j)-heterocyclyl-(CH₂)_(k)—,        —(CH₂)_(j)-aryl-(O)_(h)—(CH₂)_(k)— or        —(CH₂)_(j)-heteroaryl-(O)_(h)—(CH₂)_(k)—, each of which can        optionally be substituted;    -   Y is —ONO₂ or

-   -   m is 0, 1, 2, 3, 4 or 5;    -   j is 0, 1, 2 or 3;    -   k is 0, 1, 2 or 3; and    -   h is 0 or 1;        or a pharmaceutically acceptable salt, solvate, hydrate,        clathrate, polymorph or stereoisomer thereof.        2. The compound of embodiment 1, which is of Formula Ia:

wherein:

-   -   R¹, R², X and Y are as defined in embodiment 1; and    -   n is 1, 2, 3, 4, 5 or 6;        or a pharmaceutically acceptable salt, solvate, hydrate,        clathrate, polymorph or stereoisomer thereof.        3. The compound of embodiment 1, which is of Formula IA:

-   -   wherein R¹, R², R³, R⁴, R⁵, X and m are as defined in embodiment        1;    -   or a pharmaceutically acceptable salt, solvate, hydrate,        clathrate, polymorph or stereoisomer thereof.        4. The compound of embodiment 3, which is of Formula IAa:

wherein:

-   -   R¹, R² and X are as defined in embodiment 1; and    -   n is 1, 2, 3, 4, 5 or 6;        or a pharmaceutically acceptable salt, solvate, hydrate,        clathrate, polymorph or stereoisomer thereof.        5. The compound of embodiment 1, which is of Formula IB:

-   -   wherein R¹, R², R³, R⁴, R⁵, X and m are as defined in embodiment        1;    -   or a pharmaceutically acceptable salt, solvate, hydrate,        clathrate, polymorph or stereoisomer thereof.        6. The compound of embodiment 5, which is of Formula IBa:

wherein:

-   -   R¹, R² and X are as defined in embodiment 1; and    -   n is 1, 2, 3, 4, 5 or 6;        or a pharmaceutically acceptable salt, solvate, hydrate,        clathrate, polymorph or stereoisomer thereof.        7. The compound of any one of the preceding embodiments, wherein        X of the compound of Formula I, Ia, IA, IAa, IB or IBa is bond,        linear or branched C₁-C₆ or C₁-C₃-alkyl-, or linear or branched        C₁-C₆ or C₁-C₃—O-alkyl-.        8. The compound of embodiment 7, wherein X of the compound of        Formula I, Ia, IA, IAa, IB or IBa is bond or linear or branched        C₁-C₃-alkyl- [e.g., —CH₂—, —(CH₂)₂—, —CHCH₃, —(CH₂)₃—,        —CHCH₂CH₃, —CH₂CHCH₃ or —CH(CH₃)CH₂—].        9. A compound of Formula II or Formula III:

wherein:

-   -   R¹ and R² independently are hydrogen, halide, linear or branched        alkyl, linear or branched heteroalkyl, linear or branched        alkoxy, linear or branched —O-heteroalkyl, cycloalkyl,        heterocyclyl, aryl or heteroaryl, each of which can optionally        be substituted;    -   R³ and R⁴ independently are hydrogen or linear or branched C₁-C₆        alkyl, or R³, R⁴ and the nitrogen atom to which they are        attached form a 3-8-membered heterocyclic ring;    -   R⁵ is hydrogen or linear or branched C₁-C₆ alkyl;    -   X is bond, linear or branched -alkyl-, linear or branched        -heteroalkyl-, linear or branched —O-alkyl-, linear or branched        —O-heteroalkyl-, —(CH₂)_(j)-cycloalkyl-(CH₂)_(k)—,        —(CH₂)_(j)-heterocyclyl-(CH₂)_(k)—,        —(CH₂)_(j)-aryl-(O)_(h)—(CH₂)_(k)— or        —(CH₂)_(j)-heteroaryl-(O)_(h)—(CH₂)_(k)—, each of which can        optionally be substituted; ONO₂    -   Y is —ONO₂ or

-   -   m is 0, 1, 2, 3, 4 or 5;    -   j is 0, 1, 2 or 3;    -   k is 0, 1, 2 or 3; and    -   h is 0 or 1;        or a pharmaceutically acceptable salt, solvate, hydrate,        clathrate, polymorph or stereoisomer thereof.        10. The compound of embodiment 9, which is of Formula IV:

wherein:

-   -   R¹, R², X and Y are as defined in embodiment 9; and    -   p is 0, 1, 2, 3, 4, 5 or 6;        or a pharmaceutically acceptable salt, solvate, hydrate,        clathrate, polymorph or stereoisomer thereof.    -   11. The compound of embodiment 10, which is of Formula IVa:

wherein:

-   -   X and Y are as defined in embodiment 9; and    -   p is 0, 1, 2, 3, 4, 5 or 6;        or a pharmaceutically acceptable salt, solvate, hydrate,        clathrate, polymorph or stereoisomer thereof.        12. The compound of embodiment 9, which is of Formula IIA or        Formula IIIA:

-   -   wherein R¹, R², R³, R⁴, R⁵, X and m are as defined in embodiment        9;    -   or a pharmaceutically acceptable salt, solvate, hydrate,        clathrate, polymorph or stereoisomer thereof.        13. The compound of embodiment 12, which is of Formula IVA:

wherein:

-   -   R¹, R² and X are as defined in embodiment 9; and    -   p is 0, 1, 2, 3, 4, 5 or 6;        or a pharmaceutically acceptable salt, solvate, hydrate,        clathrate, polymorph or stereoisomer thereof.        14. The compound of embodiment 13, which is of Formula IVAa:

wherein:

-   -   X is as defined in embodiment 9; and    -   p is 0, 1, 2, 3, 4, 5 or 6;        or a pharmaceutically acceptable salt, solvate, hydrate,        clathrate, polymorph or stereoisomer thereof.        15. The compound of embodiment 9, which is of Formula IIB or        Formula IIIB:

-   -   wherein R¹, R², R³, R⁴, R⁵, X and m are as defined in embodiment        9;    -   or a pharmaceutically acceptable salt, solvate, hydrate,        clathrate, polymorph or stereoisomer thereof.        16. The compound of embodiment 15, which is of Formula IVB:

wherein:

-   -   R¹, R² and X are as defined in embodiment 9; and    -   p is 0, 1, 2, 3, 4, 5 or 6;        or a pharmaceutically acceptable salt, solvate, hydrate,        clathrate, polymorph or stereoisomer thereof.        17. The compound of embodiment 16, which is of Formula IVBa:

wherein:

-   -   X is as defined in embodiment 9; and    -   p is 0, 1, 2, 3, 4, 5 or 6;        or a pharmaceutically acceptable salt, solvate, hydrate,        clathrate, polymorph or stereoisomer thereof.        18. The compound of any one of embodiments 9 to 17, wherein the        —X—Y, —X—ONO₂ or —X—CH(ONO₂)CH₂—ONO₂ moiety is attached to a        meta position of the phenyl ring.        19. The compound of any one of embodiments 9 to 18, wherein X of        the compound of Formula II, IIA, IIB, III, IIIA, IIIB, IV, IVa,        IVA, IVAa, IVB or IVBa is bond, linear or branched C₁-C₆ or        C₁-C₃-alkyl-, or linear or branched C₁-C₆ or C₁-C₃—O-alkyl-.        20. The compound of any one of the preceding embodiments,        wherein:    -   m is 0, 1 or 2;    -   n is 1, 2 or 3; or    -   p is 0, 1, 2 or 3.        21. The compound of any one of the preceding embodiments,        wherein both R³ and R⁴ are hydrogen.        22. The compound of any one of embodiments 1 to 20, wherein one        of R³ and R⁴ is hydrogen, and the other is linear or branched        C₁-C₃ alkyl (e.g., methyl or ethyl).        23. The compound of any one of embodiments 1 to 20, wherein R³        and R⁴ independently are linear C₁-C₃ alkyl (e.g., methyl or        ethyl), optionally the same alkyl group.        24. The compound of any one of the preceding embodiments,        wherein R⁵ is hydrogen.        25. The compound of any one of embodiments 1 to 23, wherein R⁵        is linear or branched C₁-C₃ alkyl (e.g., methyl or ethyl).        26. The compound of any one of the preceding embodiments,        wherein R¹ and R² independently are hydrogen or linear or        branched C₁-C₆ alkyl.        27. The compound of embodiment 26, wherein R¹ and R²        independently are hydrogen or linear or branched C₁-C₃ alkyl        (e.g., methyl, ethyl or n-propyl).        28. The compound of embodiment 26 or 27, wherein both R¹ and R²        are hydrogen.        29. The compound of embodiment 26 or 27, wherein R¹ is hydrogen        and R² is linear or branched C₁-C₆ or C₁-C₃ alkyl (e.g., methyl,        ethyl or n-propyl), or R² is hydrogen and R¹ is linear or        branched C₁-C₆ or C₁-C₃ alkyl (e.g., methyl, ethyl or n-propyl).        30. The compound of embodiment 26 or 27, wherein R¹ and R²        independently are linear or branched C₁-C₆ or C₁-C₃ alkyl (e.g.,        methyl, ethyl or n-propyl), optionally the same alkyl group.        31. The compound of any one of the preceding embodiments,        wherein the R¹ group, the R² group or the X group, or any        combination or all thereof, independently are substituted with        1, 2 or 3 substituents selected from linear or branched C₁-C₆ or        C₁-C₃ alkyl, haloalkyl, —OR⁶, —NR⁷R⁸, —ONO₂, —CN, —C(═O)R⁶,        —C(═O)OR⁶, —OC(═O)R⁶, —C(═O)NR⁷R⁸, —NR⁷C(═O)R⁶, —OC(═O)OR⁶,        —OC(═O)NR⁷R⁸, —NR⁷C(═O)OR⁶, —NR⁶C(═O)NR⁷R⁸, aryl and heteroaryl,        or/and are substituted with 1 to 6 halogen (e.g., fluorine) or        deuterium atoms or have all available hydrogen atoms replaced        with halogen (e.g., fluorine) or deuterium atoms, wherein:    -   R⁶ in each occurrence independently is hydrogen or linear or        branched C₁-C₆ or C₁-C₃ alkyl; and    -   R¹ and R⁸ in each occurrence independently are hydrogen or        linear or branched C₁-C₆ or C₁-C₃ alkyl, or R⁷, R⁸ and the        nitrogen atom to which they are attached form a 3-6-membered        ring.        32. The compound of embodiment 31, wherein the R¹ group, the R²        group or the X group, or any combination or all thereof,        independently are deuteroalkyl, fluoroalkyl or alkyl-ONO₂.        33. The compound of any one of the preceding embodiments,        wherein X has 0, 1, 2, 3, 4, 5 or 6 carbon atoms.        34. The compound of embodiment 33, wherein X has 0, 1, 2 or 3        carbon atoms.        35. The compound of any one of the preceding embodiments, which        is a hydrochloride (HCl) or hydrobromide (HBr) salt.        36. A compound of Formula IAa selected from the compounds shown        in Table 1:

TABLE 1 For each subgenus IAa-i, IAa-ii, IAa-iii, IAa-iv, IAa-v, IAa-vi,IAa- vii, IAa-viii, IAa-ix, IAa-x, IAa-xi, IAa-xii, IAa-xiii, IAa-xiv,IAa-xv, IAa-xvi, IAa-xvii, IAa-viii, IAa-xix and IAa-xx n R¹ R² 1, 2 and3 methyl methyl 1, 2 and 3 hydrogen methyl 1, 2 and 3 methyl hydrogen 1,2 and 3 ethyl ethyl 1, 2 and 3 hydrogen ethyl 1, 2 and 3 ethyl hydrogen1, 2 and 3 n-propyl n-propyl 1, 2 and 3 hydrogen n-propyl 1, 2 and 3n-propyl hydrogen 1, 2 and 3 isopropyl isopropyl 1, 2 and 3 hydrogenisopropyl 1, 2 and 3 isopropyl hydrogen 1, 2 and 3 n-butyl n-butyl 1, 2and 3 hydrogen n-butyl 1, 2 and 3 n-butyl hydrogen 1, 2 and 3 isobutylisobutyl 1, 2 and 3 hydrogen isobutyl 1, 2 and 3 isobutyl hydrogen 1, 2and 3 sec-butyl sec-butyl 1, 2 and 3 hydrogen sec-butyl 1, 2 and 3sec-butyl hydrogen 1, 2 and 3 —CH₂—ONO₂ —CH₂—ONO₂ 1, 2 and 3 hydrogen—CH₂—ONO₂ 1, 2 and 3 —CH₂—ONO₂ hydrogen 1, 2 and 3 —(CH₂)₂—ONO₂—(CH₂)₂—ONO₂ 1, 2 and 3 hydrogen —(CH₂)₂—ONO₂ 1, 2 and 3 —(CH₂)₂—ONO₂hydrogen 1, 2 and 3 —(CH₂)₃—ONO₂ —(CH₂)₃—ONO₂ 1, 2 and 3 hydrogen—(CH₂)₃—ONO₂ 1, 2 and 3 —(CH₂)₃—ONO₂ hydrogen 1, 2 and 3 —CH₂CH(ONO₂)CH₃—CH₂CH(ONO₂)CH₃ 1, 2 and 3 hydrogen —CH₂CH(ONO₂)CH₃ 1, 2 and 3—CH₂CH(ONO₂)CH₃ hydrogen 1, 2 and 3 —CH₂CH(CH₃)CH₂—ONO₂—CH₂CH(CH₃)CH₂—ONO₂ 1, 2 and 3 hydrogen —CH₂CH(CH₃)CH₂—ONO₂ 1, 2 and 3—CH₂CH(CH₃)CH₂—ONO₂ hydrogenand pharmaceutically acceptable salts (e.g., HCl and HBr salts),solvates, hydrates, clathrates, polymorphs and stereoisomers thereof.37. The compound of embodiment 36, which is selected from:

and pharmaceutically acceptable salts (e.g., HCl and HBr salts),solvates, hydrates, clathrates, polymorphs and stereoisomers thereof,wherein Et=ethyl and Pr=n-propyl.38. A compound of Formula IBa selected from the compounds shown in Table2:

TABLE 2 For each subgenus IBa-i, IBa-ii, IBa-iii, IBa-iv, IBa-v, IBa-vi,IBa-vii and IBa-viii n R¹ R² 1, 2 and 3 methyl methyl 1, 2 and 3hydrogen methyl 1, 2 and 3 methyl hydrogen 1, 2 and 3 ethyl ethyl 1, 2and 3 hydrogen ethyl 1, 2 and 3 ethyl hydrogen 1, 2 and 3 n-propyln-propyl 1, 2 and 3 hydrogen n-propyl 1, 2 and 3 n-propyl hydrogen 1, 2and 3 isopropyl isopropyl 1, 2 and 3 hydrogen isopropyl 1, 2 and 3isopropyl hydrogen 1, 2 and 3 n-butyl n-butyl 1, 2 and 3 hydrogenn-butyl 1, 2 and 3 n-butyl hydrogen 1, 2 and 3 isobutyl isobutyl 1, 2and 3 hydrogen isobutyl 1, 2 and 3 isobutyl hydrogen 1, 2 and 3sec-butyl sec-butyl 1, 2 and 3 hydrogen sec-butyl 1, 2 and 3 sec-butylhydrogen 1, 2 and 3 —CH₂—ONO₂ —CH₂—ONO₂ 1, 2 and 3 hydrogen —CH₂—ONO₂ 1,2 and 3 —CH₂—ONO₂ hydrogen 1, 2 and 3 —(CH₂)₂—ONO₂ —(CH₂)₂—ONO₂ 1, 2 and3 hydrogen —(CH₂)₂—ONO₂ 1, 2 and 3 —(CH₂)₂—ONO₂ hydrogen 1, 2 and 3—(CH₂)₃—ONO₂ —(CH₂)₃—ONO₂ 1, 2 and 3 hydrogen —(CH₂)₃—ONO₂ 1, 2 and 3—(CH₂)₃—ONO₂ hydrogen 1, 2 and 3 —CH₂CH(ONO₂)CH₃ —CH₂CH(ONO₂)CH₃ 1, 2and 3 hydrogen —CH₂CH(ONO₂)CH₃ 1, 2 and 3 —CH₂CH(ONO₂)CH₃ hydrogen 1, 2and 3 —CH₂CH(CH₃)CH₂—ONO₂ —CH₂CH(CH₃)CH₂—ONO₂ 1, 2 and 3 hydrogen—CH₂CH(CH₃)CH₂—ONO₂ 1, 2 and 3 —CH₂CH(CH₃)CH₂—ONO₂ hydrogenand pharmaceutically acceptable salts (e.g., HCl and HBr salts),solvates, hydrates, clathrates, polymorphs and stereoisomers thereof.39. The compound of embodiment 38, which is selected from:

and pharmaceutically acceptable salts (e.g., HCl and HBr salts),solvates, hydrates, clathrates, polymorphs and stereoisomers thereof,wherein Et=ethyl and Pr=n-propyl.40. A compound of Formula IVA selected from the compounds shown in Table3:

TABLE 3 For each subgenus IVA-i, IVA-ii, IVA-iii, IVA-iv, IVA-v, IVA-viand IVA-vii p R¹ R² 0, 1, 2 and 3 hydrogen hydrogen 0, 1, 2 and 3 methylmethyl 0, 1, 2 and 3 hydrogen methyl 0, 1, 2 and 3 methyl hydrogen 0, 1,2 and 3 ethyl ethyl 0, 1, 2 and 3 hydrogen ethyl 0, 1, 2 and 3 ethylhydrogen 0, 1, 2 and 3 n-propyl n-propyl 0, 1, 2 and 3 hydrogen n-propyl0, 1, 2 and 3 n-propyl hydrogen 0, 1, 2 and 3 isopropyl isopropyl 0, 1,2 and 3 hydrogen isopropyl 0, 1, 2 and 3 isopropyl hydrogen 0, 1, 2 and3 n-butyl n-butyl 0, 1, 2 and 3 hydrogen n-butyl 0, 1, 2 and 3 n-butylhydrogen 0, 1, 2 and 3 isobutyl isobutyl 0, 1,2 and 3 hydrogen isobutyl0, 1, 2 and 3 isobutyl hydrogen 0, 1, 2 and 3 sec-butyl sec-butyl 0, 1,2 and 3 hydrogen sec-butyl 0, 1, 2 and 3 sec-butyl hydrogen 0, 1, 2 and3 —CH₂—ONO₂ —CH₂—ONO₂ 0, 1, 2 and 3 hydrogen —CH₂—ONO₂ 0, 1, 2 and 3—CH₂—ONO₂ hydrogen 0, 1, 2 and 3 —(CH₂)₂—ONO₂ —(CH₂)₂—ONO₂ 0, 1, 2 and 3hydrogen —(CH₂)₂—ONO₂ 0, 1, 2 and 3 —(CH₂)₂—ONO₂ hydrogen 0, 1, 2 and 3—(CH₂)₃—ONO₂ —(CH₂)₃—ONO₂ 0, 1, 2 and 3 hydrogen —(CH₂)₃—ONO₂ 0, 1,2 and3 —(CH₂)₃—ONO₂ hydrogen 0, 1, 2 and 3 —CH₂CH(ONO₂)CH₃ —CH₂CH(ONO₂)CH₃ 0,1, 2 and 3 hydrogen —CH₂CH(ONO₂)CH₃ 0, 1, 2 and 3 —CH₂CH(ONO₂)CH₃hydrogen 0, 1, 2 and 3 —CH₂CH(CH₃)CH₂—ONO₂ —CH₂CH(CH₃)CH₂—ONO₂ 0, 1, 2and 3 hydrogen —CH₂CH(CH₃)CH₂—ONO₂ 0, 1, 2 and 3 —CH₂CH(CH₃)CH₂—ONO₂hydrogenand pharmaceutically acceptable salts (e.g., HCl and HBr salts),solvates, hydrates, clathrates, polymorphs and stereoisomers thereof.41. The compound of embodiment 40, which is selected from:

and pharmaceutically acceptable salts (e.g., HCl and HBr salts),solvates, hydrates, clathrates, polymorphs and stereoisomers thereof.42. A compound of Formula IVB selected from the compounds shown in Table4:

TABLE 4 For each subgenus IVB-i, IVB-ii, IVB-iii, IVB-iv, IVB-v andIVB-vi p R¹ R² 0, 1, 2 and 3 hydrogen hydrogen 0, 1, 2 and 3 methylmethyl 0, 1, 2 and 3 hydrogen methyl 0, 1, 2 and 3 methyl hydrogen 0, 1,2 and 3 ethyl ethyl 0, 1, 2 and 3 hydrogen ethyl 0, 1, 2 and 3 ethylhydrogen 0, 1, 2 and 3 n-propyl n-propyl 0, 1, 2 and 3 hydrogen n-propyl0, 1, 2 and 3 n-propyl hydrogen 0, 1, 2 and 3 isopropyl isopropyl 0, 1,2 and 3 hydrogen isopropyl 0, 1, 2 and 3 isopropyl hydrogen 0, 1, 2 and3 n-butyl n-butyl 0, 1, 2 and 3 hydrogen n-butyl 0, 1, 2 and 3 n-butylhydrogen 0, 1, 2 and 3 isobutyl isobutyl 0, 1, 2 and 3 hydrogen isobutyl0, 1, 2 and 3 isobutyl hydrogen 0, 1, 2 and 3 sec-butyl sec-butyl 0, 1,2 and 3 hydrogen sec-butyl 0, 1, 2 and 3 sec-butyl hydrogen 0, 1, 2 and3 —CH₂—ONO₂ —CH₂—ONO₂ 0, 1, 2 and 3 hydrogen —CH₂—ONO₂ 0, 1, 2 and 3—CH₂—ONO₂ hydrogen 0, 1, 2 and 3 —(CH₂)₂—ONO₂ —(CH₂)₂—ONO₂ 0, 1, 2 and 3hydrogen —(CH₂)₂—ONO₂ 0, 1, 2 and 3 —(CH₂)₂—ONO₂ hydrogen 0, 1, 2 and 3—(CH₂)₃—ONO₂ —(CH₂)₃—ONO₂ 0, 1, 2 and 3 hydrogen —(CH₂)₃—ONO₂ 0, 1, 2and 3 —(CH₂)₃—ONO₂ hydrogen 0, 1, 2 and 3 —CH₂CH(ONO₂)CH₃—CH₂CH(ONO₂)CH₃ 0, 1, 2 and 3 hydrogen —CH₂CH(ONO₂)CH₃ 0, 1, 2 and 3—CH₂CH(ONO₂)CH₃ hydrogen 0, 1, 2 and 3 —CH₂CH(CH₃)CH₂—ONO₂—CH₂CH(CH₃)CH₂—ONO₂ 0, 1, 2 and 3 hydrogen —CH₂CH(CH₃)CH₂—ONO₂ 0, 1, 2and 3 —CH₂CH(CH₃)CH₂—ONO₂ hydrogenand pharmaceutically acceptable salts (e.g., HCl and HBr salts),solvates, hydrates, clathrates, polymorphs and stereoisomers thereof.43. The compound of embodiment 42, which is selected from:

and pharmaceutically acceptable salts (e.g., HCl and HBr salts),solvates, hydrates, clathrates, polymorphs and stereoisomers thereof.44. A pharmaceutical composition comprising a compound of any one of thepreceding embodiments, or a pharmaceutically acceptable salt, solvate,hydrate, clathrate, polymorph or stereoisomer thereof, and one or morepharmaceutically acceptable excipients or carriers.45. A method of treating a disorder of the central nervous system (CNS),comprising administering to a subject in need of treatment atherapeutically effective amount of a compound of any one of embodiments1 to 43, or a pharmaceutically acceptable salt, solvate, hydrate,clathrate, polymorph or stereoisomer thereof.46. The method of embodiment 45, wherein the CNS disorder is aneurodegenerative disorder.47. The method of embodiment 46, wherein the neurodegenerative disorderis selected from dementia (e.g., Alzheimer's disease, vascular dementia,dementia with Lewy bodies, frontotemporal dementia and HIV-associateddementia), Huntington's disease, Parkinson's disease, multiple systematrophy (Shy-Drager syndrome), cerebellar degeneration, ataxia (e.g.,cerebellar ataxia, spinocerebellar ataxia, Friedreich's ataxia andataxia-telangiectasia [Louis-Bar syndrome]), motor neuron diseases(e.g., amyotrophic lateral sclerosis [ALS], primary lateral sclerosis[PLS], progressive muscular atrophy [PMA] and spinal muscular atrophy[SMA]), multiple sclerosis, vision impairment or loss caused byneurodegeneration of the visual pathway (e.g., optic neuropathy/atrophy,glaucoma and age-related macular degeneration), and sensorineuralhearing loss.48. The method of embodiment 47, wherein the neurodegenerative disorderis Alzheimer's disease, vascular dementia, Huntington's disease,Parkinson's disease or ALS.49. The method of embodiment 45, wherein the CNS disorder is selectedfrom cerebrovascular disorders (including brain ischemia [includingacute ischemia such as stroke, chronic ischemia such as vasculardementia, cerebral ischemia/reperfusion injury, and neurological damagecaused by low oxygen or/and glucose levels in the brain], intracerebralhemorrhage and retinopathy), brain injury and trauma (includingtraumatic brain injury, diffuse axonal injury, primary and secondarybrain injury, focal and diffuse brain injury, anoxic and hypoxic braininjury, intracerebral hemorrhage and brain edema), spinal cord injury(due to, e.g., trauma, ischemia or a degenerative disorder), epilepsy(including neurological damage caused by epileptic seizures), dyskinesia(e.g., levodopa-induced dyskinesia and tardive dyskinesia), spasticity,pain (e.g., acute pain, chronic pain, allodynia, complex regional painsyndrome [CRPS], fibromyalgia, hyperalgesia, inflammatory pain,neuropathic pain, postoperative pain, cancer-related pain, drug-inducedpain and injury-induced pain), headaches (including primary headaches[e.g., migraine, cluster headache and tension headache] and secondaryheadaches [due to, e.g., a cerebrovascular disorder, a brain bleed, abrain injury, a brain infection or a brain tumor), neurodevelopmentaldisorders (including MEF2C haploinsufficiency syndrome [MCHS], autismspectrum disorder [including autism], developmental delay, intellectualdisability, fragile X syndrome, attention-deficit hyperactivity disorder[ADHD] and schizophrenia), mood disorders (including depressivedisorders [e.g., major depressive disorder and treatment-resistantdepression], bipolar disorders and dementia-related mood disorders), andanxiety disorders (including generalized anxiety disorder, stressdisorders [e.g., acute stress disorder, post-traumatic stress disorderand chronic stress], and obsessive-compulsive disorder).50. The method of embodiment 49, wherein the CNS disorder is brainischemia, traumatic brain injury, epilepsy, pain or autism spectrumdisorder.51. The method of any one of embodiments 45 to 50, wherein the compoundis administered orally.52. The method of any one of embodiments 45 to 50, wherein the compoundis administered parenterally (e.g., intravenously, intramuscularly orsubcutaneously).53. The method of any one of embodiments 45 to 52, wherein the compoundis administered in a daily dose of from about 1, 5 or 10 mg to about 100mg.54. The method of embodiment 53, wherein the compound is administered ina daily dose of about 1, 5, 10, 15, 20, 25, 30, 40, 50, 60, 70, 80, 90or 100 mg.55. The method of embodiment 53 or 54, wherein the compound isadministered in a daily dose of from about 5 or 10 mg to about 50 mg.56. The method of any one of embodiments 45 to 55, further comprisingadministering an additional therapeutic agent.57. A compound of any one of embodiments 1 to 43, or a pharmaceuticallyacceptable salt, solvate, hydrate, clathrate, polymorph or stereoisomerthereof, for use as a medicament.58. A composition comprising a compound of any one of embodiments 1 to43, or a pharmaceutically acceptable salt, solvate, hydrate, clathrate,polymorph or stereoisomer thereof, for use as a medicament.59. Use of a compound of any one of embodiments 1 to 43, or apharmaceutically acceptable salt, solvate, hydrate, clathrate, polymorphor stereoisomer thereof, in the preparation of a medicament.60. The compound, composition or use of embodiment 57, 58 or 59,respectively, wherein the medicament is for use in the treatment of aCNS disorder, such as a neurodegenerative disorder or anon-neurodegenerative disorder.61. A kit comprising:

-   -   a compound of any one of embodiments 1 to 43, or a        pharmaceutically acceptable salt, solvate, hydrate, clathrate,        polymorph or stereoisomer thereof; and    -   instructions for administering the compound to treat a CNS        disorder, such as a neurodegenerative disorder or a        non-neurodegenerative disorder.

X. EXAMPLES

The following examples are intended only to illustrate the disclosure.Other synthetic processes, assays, studies, protocols, procedures,methodologies, reagents and conditions may alternatively be used asappropriate.

Abbreviations: DCM=dichloromethane; DMF=N,N-dimethylformamide;EGTA=ethylene glycol-bis(β-aminoethyl ether)-N,N,N′,N′-tetraacetic acid;HEPES=4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid; MTBE=methyltert-butyl ether; PBS=phosphate-buffered saline; RT=room/ambienttemperature; TEA=triethylamine; THF=tetrahydrofuran

Synthesis of Aminoadamantyl Nitrate Compounds

Representative syntheses of compounds of Formulas I and III are shownbelow.

Example 1. Synthesis of1-Aminomethylene-3,5-dimethyl-7-nitratemethyladamantane Hydrochloride

To a solution of 1-carboxy-3,5-dimethyladamantane (5 g, 24 mmol,available from Sigma-Aldrich) in DCM (20 mL) was added DMF (2 drops)followed by oxalyl chloride (6.2 mL, 72 mmol) dropwise. The reactionmixture was stirred overnight at room temperature and then concentratedin vacuo. The resulting oil was diluted in THF (10 mL) and added to anice-cooled solution of THF (20 mL) and 28% ammonium hydroxide (5 mL).The reaction was stirred for 1 hr, diluted with MTBE, washed with brine,dried over sodium sulfate and concentrated to give1-carboxamide-3,5-dimethyladamantane as a white solid.

1-Carboxamide-3,5-dimethyladamantane (2 g, 9.7 mmol) was added to fumingsulfuric acid (30 mL) at 0° C. over 1 hr. The reaction mixture wasstirred at 0° C. for 2 hr and then was treated with 95% formic acid (4mL) dropwise. The mixture was stirred at 0° C. for 2 hr and then waspoured carefully onto ice (200 g). The precipitate was filtered, washedwith water and dried under vacuum to afford1-carboxamide-3,5-dimethyl-7-carboxy adamantane.

LiAlH₄ (1 M in THF, 4 mL) was added to a solution of1-carboxamide-3,5-dimethyl-7-carboxyadamantane (620 mg, 2.5 mmol) in THF(15 mL). The reaction mixture was stirred at 40° C. for 24 hr, and thenwas quenched with Glauber's salt, diluted with ether, and stirred for 1hr. The solids were removed by filtration, and the organic layer of thefiltrate was concentrated. The residue was dissolved in acetonitrile (10mL) and treated with saturated sodium bicarbonate solution (10 mL) andBOC₂O (545 mg, 2.5 mmol), and the resulting mixture was stirred for 8hr. The mixture was diluted with MTBE, washed with brine, dried oversodium sulfate, and concentrated. The residue was purified by silica gelcolumn chromatography (10-100% EtOAc/hexanes) to give1-(N-Boc-aminomethylene)-3,5-dimethyl-7-hydroxymethyladamantane. MS: m/z324 [M+H]⁺

A chilled solution (0° C.) of acetyl nitrate (420 μL) formed from amixture of fuming nitric acid and acetic anhydride (1:1.5 v/v) was addedto a solution of1-(N-Boc-aminomethylene)-3,5-dimethyl-7-hydroxymethyladamantane (225 mg,0.7 mmol) in DCM (5 mL) at 0° C. The reaction mixture was stirred coldfor 15 min and then was quenched with saturated sodium bicarbonate,extracted into DCM, washed with water, dried over sodium sulfate andconcentrated. The residue was purified by silica gel columnchromatography (10-50% EtOAc/hexanes) to give1-(N-Boc-aminomethylene)-3,5-dimethyl-7-nitratemethyladamantane. MS: m/z369 [M+H]⁺

A solution of HCl in dioxane (4 N, 2 mL) was added to1-(N-Boc-aminomethylene)-3,5-dimethyl-7-nitratemethyladamantane (150mg). The reaction mixture was stirred at room temperature for 30 min andthen was concentrated in vacuo. The residue was triturated with etherand filtered to provide1-aminomethylene-3,5-dimethyl-7-nitratemethyladamantane hydrochloride.MS: m/z 269 [M+H]⁺

The following compounds were synthesized using similar procedures asabove: 1-(2-aminoethyl)-3,5-dimethyl-7-nitratemethyladamantanehydrochloride starting from 1-acetic acid-3,5-dimethyladamantane(available from Sigma-Aldrich).

Example 2. Synthesis of1-Aminomethylene-3,5-dimethyl-7-nitrateadamantane Hydrochloride

1-Carboxamide-3,5-dimethyladamantane (2 g, 9.7 mmol, prepared asdescribed in Example 1) was added to fuming sulfuric acid (30 mL) at 0°C. over 1 hr. The reaction mixture was stirred at 0° C. for 2 hr andthen was poured carefully onto ice (200 g). The precipitate wasfiltered, washed with water and dried under vacuum to give1-carboxamide-3,5-dimethyl-7-hydroxyadamantane. MS: m/z 224 [M+H]+

LiATH₄ (1 M in THF, 5 mL) was added to a solution of1-carboxamide-3,5-dimethyl-7-hydroxyadamantane (830 mg, 3.7 mmol) in THF(20 mL). The reaction mixture was stirred at 40° C. for 24 hr, and thenwas quenched with Glauber's salt, diluted with ether, and stirred for 1hr. The solids were removed by filtration, and the organic layer of thefiltrate was concentrated. The residue was dissolved in acetonitrile (10mL) and treated with saturated sodium bicarbonate solution (10 mL) andBOC₂O (806 mg, 3.7 mmol), and the resulting mixture was stirred for 10hr. The mixture was diluted with MTBE, washed with brine, dried oversodium sulfate, and concentrated. The residue was purified by silica gelcolumn chromatography (10-100% EtOAc/hexanes) to afford1-(N-Boc-aminomethylene)-3,5-dimethyl-7-hydroxyadamantane. MS: m/z 310[M+H]⁺

A chilled solution (0° C.) of acetyl nitrate (300 μL) formed from amixture of fuming nitric acid and acetic anhydride (1:1.5 v/v) was addedto a solution of1-(N-Boc-aminomethylene)-3,5-dimethyl-7-hydroxyadamantane (150 mg, 0.5mmol) in DCM (3 mL) at 0° C. The reaction mixture was stirred cold for15 min and then was quenched with saturated sodium bicarbonate,extracted into DCM, washed with water, dried over sodium sulfate andconcentrated. The residue was purified by silica gel columnchromatography (10-50% EtOAc/hexanes) to furnish1-(N-Boc-aminomethylene)-3,5-dimethyl-7-nitrateadamantane. MS: m/z 355[M+H]⁺

A solution of HCl in dioxane (4 N, 2 mL) was added to1-(N-Boc-aminomethylene)-3,5-dimethyl-7-nitrateadamantane (85 mg). Thereaction mixture was stirred at room temperature for 30 min and then wasconcentrated in vacuo. The residue was triturated with ether andfiltered to provide 1-aminomethylene-3,5-dimethyl-7-nitrateadamantanehydrochloride. MS: m/z 255 [M+H]⁺

The following compounds can be synthesized using similar procedures asabove: 1-(2-aminoethyl)-3,5-dimethyl-7-nitrateadamantane hydrochloridestarting from 1-acetic acid-3,5-dimethyladamantane (available fromSigma-Aldrich).

Example 3. Synthesis of1-(2-Aminoethyl)-3,5-dimethyl-7-(1-nitratepropyl)adamantaneHydrochloride

1-Carboxamidemethyl-3,5-dimethyl-7-carboxyadamantane was preparedstarting from 1-acetic acid-3,5-dimethyladamantane (available fromSigma-Aldrich) using similar procedures as described for the preparationof 1-carboxamide-3,5-dimethyl-7-carboxyadamantane starting from1-carboxy-3,5-dimethyladamantane in Example 1. The methyl ester wasformed using TMS diazomethane.

Ethylmagnesium bromide (3 M in ether, 208 mg, 1.6 mmol) was added to acooled solution of 1-carboxamidemethyl-3,5-dimethyl-7-(carboxylic acidmethyl ester)adamantane (220 mg, 0.78 mmol) in THF (5 mL) over 5 min,and the reaction mixture in the ice bath was stirred for 2 hr. Thereaction was quenched with a saturated solution of ammonium chloride andextracted with ethyl acetate. The organic layer was washed with brine,dried over sodium sulfate and concentrated to provide a crude mixture ofthe ethyl ketone and the dialkylated alcohol. Purification by silica gelcolumn chromatography using ethyl acetate/hexane as the eluent provided1-carboxamidemethyl-3,5-dimethyl-7-(propan-1-one)adamantane (86 mg).

LiAlH₄ (1 M in THF, 36 mg, 0.93 mmol) was added to a cooled (ice bath)solution of 1-carboxamidemethyl-3,5-dimethyl-7-(propan-1-one)adamantane(86 mg, 0.31 mmol) in THF (2 mL) over 5 min, and the reaction mixturewas then heated at 50° C. and stirred for 4 hr. The reaction wasquenched with sodium sulfate decahydrate. The resulting solid wasfiltered and washed with THF (2×5 mL), and the filtrate wasconcentrated. Purification by silica gel column chromatography usingDCM/methanol as the eluent furnished1-(2-aminoethyl)-3,5-dimethyl-7-(1-hydroxypropyl)adamantane (72 mg). Theamino group was protected with a Boc group using BOC₂O according to asimilar procedure as described in Example 1.

1-(2-Aminoethyl)-3,5-dimethyl-7-(1-nitratepropyl)adamantanehydrochloride was prepared starting from1-(N-Boc-2-aminoethyl)-3,5-dimethyl-7-(1-hydroxypropyl)adamantane usingsimilar procedures as described for the preparation of1-aminomethylene-3,5-dimethyl-7-nitratemethyladamantane hydrochloridestarting from1-(N-Boc-aminomethylene)-3,5-dimethyl-7-hydroxymethyladamantane inExample 1.

The following compounds can be synthesized using similar procedures asabove: 1-(Aminomethylene)-3,5-dimethyl-7-(1-nitratepropyl)adamantanehydrochloride starting from 1-carboxy-3,5-dimethyladamantane.

Furthermore, 1-(2-aminoethyl)-3,5-dimethyl-7-(1-nitrate-ethyl)adamantanehydrochloride and1-(aminomethylene)-3,5-dimethyl-7-(1-nitrate-ethyl)adamantanehydrochloride can be synthesized using similar procedures as above.MeMgBr can be reacted with the corresponding methyl ester to form themethyl ketone, or the methyl ketone can be formed by reacting MeLi withthe corresponding carboxylic acid according to the procedure describedin J. Henkel et al., J. Med. Chem., 25:51-56 (1982).

Example 4. Synthesis of 2-Aminomethylene-2-(3-nitratephenyl)adamantaneHydrochloride

3-Methoxyphenylmagnesium bromide (1 M in THF, 16 mL) was added to achilled (0° C.) solution of 2-adamantanone (2 g, 13.3 mmol, availablefrom Sigma-Aldrich) in THF (20 mL). The reaction mixture was stirred atroom temperature for 3 days over the weekend, and then was quenched withsaturated sodium bicarbonate solution, diluted with MTBE, washed withbrine, dried over sodium sulfate and concentrated. The residue waspurified by silica gel column chromatography (30% EtOAc/hexanes) to give2-hydroxy-2-(3-methoxyphenyl)adamantane.

A chilled (0° C.) solution of 2-hydroxy-2-(3-methoxyphenyl)adamantane(3.4 g, 13.2 mmol) in chloroform (10 mL) was treated with TMSCN (1.84mL, 13.9 mmol) followed by BF₃.OEt₂ (1.96 mL, 15.8 mmol). The reactionmixture was allowed to warm to room temperature and stirred for 3 hr.The reaction was quenched with sodium bicarbonate solution, extractedinto DCM, dried over sodium sulfate and concentrated. The residue waspurified by silica gel column chromatography (20% EtOAc/hexanes) toafford 2-cyano-2-(3-methoxyphenyl)adamantane.

LiAlH₄ (1 M in Et₂O, 27.8 mL) was added dropwise to a solution of2-cyano-2-(3-methoxyphenyl)adamantane (2.48 g, 9.2 mmol) in THF (20 mL),and the reaction mixture was stirred at 50° C. overnight. The mixturewas allowed to cool to room temperature, quenched with Glauber's salt,diluted with ether, and stirred for 1 hr. The solids were removed byfiltration, and the organic layer of the filtrate was concentrated. Theresidue was dissolved in acetonitrile (30 mL), treated with saturatedsodium bicarbonate solution (30 mL) and BOC₂O (2 g, 9.2 mmol), andstirred for 14 hr. The mixture was diluted with MTBE, washed with brine,dried over sodium sulfate, and concentrated. The residue was purified bysilica gel column chromatography (10-100% EtOAc/hexanes) to furnish2-(N-Boc-aminomethylene)-2-(3-methoxyphenyl)adamantane. MS: m/z 372[M+H]⁺

A solution of 2-(N-Boc-aminomethylene)-2-(3-methoxyphenyl)adamantane(1.1 g, 4.0 mmol) in dichloroethane (20 mL) was treated with BBr₃.SMe₂(1 M, 12 mmol), and the reaction mixture was stirred at 80° C. for 24hr. The reaction was quenched with saturated sodium bicarbonate, dilutedwith DCM, washed with brine, dried over sodium sulfate, andconcentrated. The residue was purified by silica gel columnchromatography (20-60% EtOAc/hexanes) to provide2-(N-Boc-aminomethylene)-2-(3-hydroxyphenyl)adamantane. MS: m/z 358[M+H]⁺

2-Aminomethylene-2-(3-nitratephenyl)adamantane hydrochloride wasprepared starting from2-(N-Boc-aminomethylene)-2-(3-hydroxyphenyl)adamantane using similarprocedures as described for the preparation of1-aminomethylene-3,5-dimethyl-7-nitratemethyladamantane hydrochloridestarting from1-(N-Boc-aminomethylene)-3,5-dimethyl-7-hydroxymethyl-adamantane inExample 1.

Example 5. Synthesis of2-Aminomethylene-2-[3-(2-nitrate-ethoxy)phenyl]adamantane Hydrochloride

A solution of 2-(N-Boc-aminomethylene)-2-(3-hydroxyphenyl)adamantane(230 mg, 0.64 mmol, prepared as described in Example 4) in DMF (5 mL)was treated with potassium carbonate (200 mg) and2-benzyloxy-1-bromoethane (172 mg, 0.8 mmol), and the reaction mixturewas stirred at 80° C. for 24 hr. The mixture was diluted with MTBE,washed with brine, dried over sodium sulfate, and concentrated. Theresidue was dissolved in ethanol (10 mL) and treated with 10% Pd—C(20mg), and the reaction mixture was stirred under 1 atm hydrogen at roomtemperature for 18 hr. The mixture was filtered, and the filtrate wasconcentrated. The residue was purified by silica gel columnchromatography (20-100% EtOAc/hexanes) to provide2-(N-Boc-aminomethylene)-2-[3-(2-hydroxyethoxy)phenyl]adamantane. MS:m/z 402 [M+H]⁺

2-Aminomethylene-2-[3-(2-nitrate-ethoxy)phenyl]adamantane hydrochloridewas prepared starting from2-(N-Boc-aminomethylene)-2-[3-(2-hydroxyethoxy)phenyl]adamantane usingsimilar procedures as described for the preparation of1-aminomethylene-3,5-dimethyl-7-nitratemethyladamantane hydrochloridestarting from1-(N-Boc-aminomethylene)-3,5-dimethyl-7-hydroxymethyl-adamantane inExample 1.

The following compounds were synthesized using similar procedures asabove: 2-Aminomethylene-2-[3-(3-nitratepropyloxy)phenyl]adamantanehydrochloride.

Example 6. Syntheses of Various Aminoadamantyl Nitrate Compounds

FIG. 1 describes the synthesis of aminoadamantyl nitrate compounds 9a-e,13a-e and 16a-e. 1-Bromoadamantanes 2b-d can be generated fromadamantanes 1b-d as described in J. Henkel et al., J. Med. Chem.,25:51-56 (1982) (“Henkel”), while 1-bromoadamantane 2a can be generatedfrom the corresponding 1-hydroxyadamantane as described in Henkel.1,3-Di-n-propyladamantane 1e can be prepared by reacting1,3-adamantanediacetic acid (available from Sigma-Aldrich) with CH₃Lifollowed by Wolff-Kishner reduction of the resulting1,3-adamantanediacetone with hydrazine, similar to the preparation of1-propyladamantane from 1-adamantaneacetic acid as described in Henkel.Adamantane 1e can be brominated using the procedure of Henkel to form1-bromoadamantane 2e. 1-Bromoadamantanes 2a-e can be converted to1-cyanoadamantanes 3a-e using NaCN or KCN at elevated temperature.Alternatively, adamantanes 1a-e can be converted to 1-carboxyadamantanes4a-e and then 1-carboxamideadamantanes 5a-e using procedures describedin Example 1.

Aminoadamantyl nitrate compounds 9a-e can be synthesized from1-cyanoadamantanes 3a-e or 1-carboxamideadamantanes 5a-e usingprocedures described for the synthesis of1-aminomethylene-3,5-dimethyl-7-nitrateadamantane hydrochloride inExample 2. Conversion of a cyano group to a —CH₂NHBoc group using LiATH₄followed by Boc₂O is described in Example 4.

Aminoadamantyl nitrate compounds 13a-e can be synthesized from1-cyanoadamantanes 3a-e or 1-carboxamideadamantanes 5a-e usingprocedures described for the synthesis of1-aminomethylene-3,5-dimethyl-7-nitratemethyladamantane hydrochloride inExample 1.

Aminoadamantyl nitrate compounds 16a-e can be synthesized from 1-(cyanoor carboxamide)-5 or 7-carboxyadamantanes 10a-e using proceduresdescribed for the synthesis of1-(2-aminoethyl)-3,5-dimethyl-7-(1-nitratepropyl)adamantanehydrochloride in Example 3. Methyl or ethyl ketones 14a-e can beprepared by reacting carboxyadamantanes 10a-e with MeLi or EtLi, similarto the preparation of 1-adamantaneacetone by reacting 1-adamantaneaceticacid with MeLi as described in Henkel. Alternatively, methyl or ethylketones 14a-e can be prepared by reacting the methyl ester of carboxylicacid 10 with MeMgBr or EtMgBr as described in Example 3.

Aminoadamantyl nitrate compounds with R¹═H and R²=Me, Et or n-Pr andcorresponding to compounds 9a, b and d, 13a, b and d, and 16a, b and dare stereoisomers of compounds 9a, b and d, 13a, b and d, and 16a, b andd. The stereoisomers can be included in a mixture (e.g., an about 1:1mixture) with compounds 9a, b and d, 13a, b and d, and 16a, b and d, orcan be separated from compounds 9a, b and d, 13a, b and d, and 16a, band d, such as by chiral high-pressure liquid chromatography (HPLC).

Biological Assays and Studies of Aminoadamantyl Nitrate Compounds

Example 7. In Vitro Inhibition of NMDAR-Evoked Current

The antagonistic activity of various aminoadamantyl nitrate compounds onNMDA receptors was assessed in a ScreenPatch IonWorks Barracuda-basedassay using HEK293 cells expressing NR1/NR2A ionotropic glutamatereceptors. The assay was conducted at ambient temperature. Extracellularbuffer (137 mM NaCl, 1 mM KCl, 5 mM CaCl₂, 10 mM HEPES, 10 mM glucose,pH 7.4) was loaded into the wells of a PPC plate (11 IL per well). Asuspension of NR1/NR2A-expressing HEK293 cells was pipetted into thewells (9 μL per well) of the PPC planar electrode whose intracellularcompartment contained an intracellular solution of 50 mM CsCl, 90 mMCsF, 2 mM MgCl₂, 5 mM EGTA, 10 mM HEPES, pH 7.2. The holding potentialwas −70 mV, and the potential during application of a test compound ormemantine HCl (positive control) was −40 mV. Whole-cell recordingconfiguration was established via patch perforation with membranecurrents recorded by on-board patch clamp amplifiers. One recording(scans) was performed during co-application of a test compound andagonist (EC₂₀ L-glutamate) to detect any PAM effect of the testcompound. Application of a test compound or memantine HCl consisted ofaddition of 20 μL of 1× or 2× concentrated solution of the test compoundor memantine HCl and co-agonists (3 μM L-glutamate and 50 μM glycine) at10 μL/s (2 second total application time). The duration ofco-exposure/co-application of a test compound or memantine HCl andco-agonists was at least 15 seconds. Activation of NMDA receptors wascalculated in three ways based on measurements of peak currentamplitudes and current amplitude 2 seconds after agonist addition. Thevehicle (agonist) control was 3 μM L-glutamate and 50 μM glycine, andthe positive control was memantine HCl. Data acquisition and analysiswere performed using IonWorks system software (Molecular DevicesCorporation, Union City, Calif.). The IC₅₀ of test compounds andmemantine HCl was calculated from a dose-response curve generated from 8different concentrations of the test compounds and memantine HCl. Thedecrease in current amplitude and current decay after co-application ofa test compound or memantine HCl and co-agonists was used to calculatethe percent NMDAR channel block.

The following aminoadamantyl nitrate compounds as a hydrochloride saltwere tested in the ScreenPatch assay:

Memantine hydrochloride and all of the aminoadamantyl nitrate compounds,except for the phenylnitrate compound, had an IC₅₀≤about 20 μM in theScreenPatch assay.

Example 8. Inhibition of NMDA Receptor Function in Patch-ClampElectrophysiology

Patch-clamp electrophysiology experiments are performed to assess theability of test compounds to block NMDA-evoked currents by a dualmechanism of channel blockade at or near the Mg²⁺-binding site andS-nitrosylation of the redox modulatory site.

Preparation of Cerebrocortical Neurons

Tissues containing parieto-occipital cortex from C57BL/6 mice areincubated twice (20 min each time) at 37° C. in Hanks' balanced saltsolution (HBSS), pH 7.22, containing 3.5 U/mL papain, 1.7 mM cysteine,20 μg/mL bovine serum albumin and NMDAR blockers (100 μM DL-APV[DL-amino-5-phosphonovaleric acid], 1 mM kynurenic acid, 10 mM MgCl₂).After being rinsed, the tissues are gently washed with a 1-mL glassserological pipette. The supernatant is placed onto glass cover slipscoated with poly-L-lysine. Cells are plated 2-10 hr beforeelectrophysiological recordings.

Electrophysiological Recordings of Dissociated Neurons

Single-channel currents from outside-out patches and whole-cell currentsfrom cerebrocortical neurons are recorded at 20-25° C. by anexperimenter masked to genotype, as described in Chen et al., JNeurosci., 12:4427-4436 (1992) and Chen et al., J. Physiol. (Lond),499:27-46 (1997). Briefly, electrodes are filled with an intracellularsolution (pH 7.22) containing 120 mM CsCl, 20 mM TEA-Cl, 10 mM HEPES,2.25 mM EGTA, 1 mM CaCl₂, and 2 mM MgCl₂. The external solution is amodified HBSS with 10 μM glycine in which Mg²⁺ salts are omitted, and└Ca²⁺┘_(O) is adjusted to 2.5 mM or lowered to the nanomolar range byadding 1 mM EGTA in the absence of added CaCl₂. (Low [Ca²⁺]_(O) is usedto minimize subconductance states during single-channel recording). Apotential problem in electrophysiology experiments is rundown of theNMDA-evoked response—keeping ┌Ca²⁺┐_(O) low and using anATP-regenerating system helps. Moreover, since dithiothreitol (DTT,0.5-2 mM) can reverse the effect of the nitrate group of aminoadamantylnitrate compounds (and of other oxidizing agents), the effects ofrundown can be distinguished from real NMDAR inhibition by NO⁺ donationto thiol group(s). When multiple compounds are tested in a singleexperiment, significance of the results is evaluated with an analysis ofvariance followed by a Scheffé multiple comparison of means. The dwelltime of the test compounds in the NMDAR channel and their effect onexcitatory postsynaptic current (EPSC) amplitude are assessed [Chen(1997, supra) and Chen et al., Neurosci., 86:1121-1132 (1998)].Memantine and nitroglycerin (NTG) are used are positive controls in theexperiments.

Example 9. Recordings of NMDAR-Mediated Currents Under Whole-Cell Clamp

The protocol for performing whole-cell recordings of NMDAR-mediatedcurrents using rat cerebrocortical cultures and hippocampal autapticcultures is described in H. Takahashi et al., Sci. Rep., 5:14781 (2015).

Example 10. Assessment of Rat Hippocampal LTP by Field Recordings

The protocol for recording extracellular field excitatory postsynapticpotentials (EPSPs) in rat hippocampus is described in H. Takahashi etal., Sci. Rep., 5:14781 (2015).

Example 11. S-Nitrosylation of NMDA Receptors

The protocol for performing S-nitrosylation of NMDA receptors in ratbrain in a biotin switch assay is described in H. Takahashi et al., Sci.Rep., 5:14781 (2015).

Example 12. In Vitro Protection Against Neurotoxicity

Mixed cerebrocortical cultures, composed of similar cell types as foundin vivo in the cerebral cortex, are used [Chen et al., Neurosci.,86:1121-1132 (1998); and Kim et al., Neuron, 24:461-469 (1999)]. Forneurotoxicity experiments using rat fetal cortical cultures, the normalculture medium is exchanged at room temperature for Earle's BalancedSalt Solution (EBSS) without phenol red. Cultures are then incubated inNMDA (dose response curve of 10 μM-1 mM) for 5 to 30 min. The culturemedium is then replaced with fresh EBSS, and the cultures are returnedto the incubator. Cultures are scored for neuronal viability at varioustimes up to 24 hr using assays that quantitate cell death anddistinguish between apoptosis and necrosis.

Mild insults with NMDA induce apoptosis (monitored by propidium iodidestaining and morphology after cell permeabilization, DNA fragmentationin agarose gels, electron microscopy, in situ labeling of DNA fragments[TUNEL and ApoTag] with morphology, and ELISA of histone-associated DNAfragments [mono- and oligonucleosomes]) [Bonfoco et al., Techniques fordistinguishing apoptosis from necrosis in cerebrocortical and cerebellarneurons, in Neuromethods: Apoptosis Techniques and Protocols, J.Poirier, Ed., pp. 237-253 (1997) (Humana, Totowa, N.J.)]. Intenseinsults with NMDA induce necrosis (monitored by histology, trypan bluestaining, and lactate dehydrogenase [LDH] leakage) [Ankarcrona et al.,Neuron, 15:961-973 (1995); Bonfoco et al., Proc. Natl. Acad. Sci. USA,92:7162-7166 (1995); Bonfoco et al. (1997, supra); and Nicotera et al.,Apoptosis, 1:5-10 (1996)]. Dose-response for protection by testcompounds is evaluated using memantine and nitroglycerin alone andcombined as controls.

In situ detection of apoptotic cells is performed by TUNEL stainingusing a commercial kit (Intergen, Purchase, N.Y.). After being washedwith PBS, cells cultured on slides are fixed with 1% paraformaldehydefor 10 min. After being washed with PBS, the adherent cultured cells areincubated with terminal deoxynucleotidyl transferase (TdT) in ahumidified chamber at 37° C. for 1 hr. After being treated withstop/wash buffer at room temperature for 10 min and three washes withPBS, cells are incubated with anti-digoxigenin conjugated withfluorescein in a humidified chamber at room temperature for 30 min.After 4 washes in PBS, the slides with adherent cultured cells arecounterstained with 0.5 μg/mL propidium iodide and mounted with a glasscover slip. The number of apoptotic cells are counted under a microscope(100× magnification).

Example 13. In Vitro Protection of Primary Cerebellum Granule Cells ofRats

Isolated primary cerebellum granule cells of infant rats are inoculatedin 96-well plates at about 1.2×10⁵ cells per well using 10% FBS+25 mMKCl+2 mM glutamine+1% of double-antibody BME medium. After 24 hours,cytarabine at a final concentration of 10 μM is added to inhibit theproliferation of neurogliocyte cells. After day 4, glucose at a finalconcentration of 5 mM is added every four days to complement energymetabolism and water evaporation of cells. The materials are placed in acell incubator (37° C., 5% CO₂) for culturing for 10 days. 200 μM ofglutamate is used to induce excitotoxic injury of the primary cerebellumgranule cells. Test groups include normal control group, glutamategroup, pretreatment groups with different aminoadamantyl nitratecompounds, and pretreatment control group with memantine. Afterpretreatment for 2 hr, 200 μM of glutamate is added to induce celldamage for 24 hr, and then MTT[3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] is addedto the culture for 4 hr. The supernatant fraction is removed, and 150 μLof DMSO is added to each well for dissolving. After blending withshaking, the light absorption values at 570 nm wavelength is measuredwith a microplate reader, and the viability of cells is calculated. Cellviability (%)=(absorbance of test group/absorbance of normal controlgroup)×100%.

Example 14. Water Maze Neurobehavioral Test in Rats

The protocol for conducting a water maze neurobehavioral test inspontaneously hypertensive rats is described in H. Takahashi et al.,Sci. Rep., 5:14781 (2015).

Example 15. In Vivo Neuroprotection in a Murine Cerebral Ischemia Model

In a mouse model of focal cerebral ischemia/reperfusion, the middlecerebral artery (MCA) of C57BL/6 mice is ligated for 2 hr using anintraluminal suture method as described in Chen et al., Neurosci.,86:1121-1132 (1998). A loading dose of a test compound or vehiclecontrol is initially administered intraperitoneally (i.p.) 2 hr afterMCA occlusion, followed by i.p. administration of a maintenance dose ofthe test compound or vehicle control every 12 hr for 48 hr. The animalsare sacrificed and analyzed with TTC staining 48 hr after MCA occlusion.Outcomes of focal cerebral ischemia/reperfusion induced by theintraluminal suture method, such as infarct area or volume, are measuredas a gage of the test compound's ability to reduce cerebral damage aftera stroke.

Example 16. In Vivo Neuroprotection in a Rat Cerebral Ischemia Model

Compounds were tested for inhibition of NMDA receptors using NMDAglutamate receptors NR1/NR2B encoded by the human GRIN1 and GRIN2Bgenes, expressed in HEK293 cells (originally from ATCC, Manassas, Va.).Cells were maintained in tissue culture incubators, and stocks weremaintained in cryogenic storage. Cells used for electrophysiology wereplated in 150-mm plastic culture dishes. HEK293 cells were transfectedwith the appropriate ion channel or receptor cDNA(s) encoding NR1 andNR2B. Stable transfectants were selected using the G418 andZeocin™-resistance genes incorporated into the expression plasmid.Selection pressure was maintained with G418 and Zeocin™ in the culturemedium. Cells were cultured in Dulbecco's Modified Eagle Medium/NutrientMixture F-12 (D-MEM/F-12) supplemented with 10% fetal bovine serum, 100U/mL penicillin G sodium, 100 μg/mL streptomycin sulfate, 100 ug/mLZeocin™, 5 ug/mL blasticidin, and 500 μg/mL G418.

Test compounds were evaluated in 8-point concentration-response format(8 replicate wells/concentration). All test and control solutionscontained 0.3% DMSO. The test article formulations were loaded in a384-well plate using an automated liquid handling system (SciCloneALH3000, Caliper LifeScienses). To verify the sensitivity the assay, theantagonist positive control article (memantine) was applied at 8concentrations (n=4, where n=the number of replicates).

The effects of the test compounds were evaluated using the IonWorks®Barracuda™ Automated Patch Clamp System. Intracellular solutioncontained 50 mM CsCl, 90 mM CsF, 2 mM MgCl2, 5 mM EGTA, and 10 mM HEPES,pH 7.2. This solution was prepared in batches and stored refrigerated.In preparation for a recording session, the intracellular solution wasloaded into the intracellular compartment of the PPC planar electrode.Extracellular solution (137 mM NaCl; 1.0 mM KCl; 5 mM CaCl₂); 10 mMHEPES; 10 mM glucose; pH 7.4. Patch clamp measurements were made with aholding potential of −70 mV, and the potential during compoundapplication was −40 mV. Extracellular buffer was loaded into the PPCplate wells (11 μL per well). Cell suspension was then pipetted into thewells (9 μL per well) of the PPC planar electrode. Whole-cell recordingconfiguration was established via patch perforation with membranecurrents recorded by on-board patch clamp amplifiers. Two recordings(scans) were performed: first, during pre-application of test articlesand, second, co-application test article with agonist (EC50 L-glutamate)and to detect inhibition of NR1/NR2B receptors by the test article. Theapplication consisted of two additions of 20 μL test solution containingantagonists at 10 μL/s (2 second total application time). First additionof 2× concentrated articles were preapplied for 5 minutes before thesecond addition of 1× concentrated articles. Data acquisition wasperformed via the IonWorks® Barracuda™ software, and data was analyzedusing Microsoft Excel (Microsoft Corp., Redmond, Wash.).Concentration-response data was fitted to a Hill equation of thefollowing form:

RESPONSE=Base+[(Max−Base)/(1+(x _(half) /x)^(rate))]

where Base is the response at low concentrations of test article, Max isthe maximum response at high concentrations, x_(half) is the EC₅₀, orIC₅₀, the concentration of test article producing either half-maximalactivation or inhibition, and rate is the Hill coefficient. Nonlinearleast squares fits were made assuming a simple binding model. Fits wereweighted by the standard deviation. No assumptions about the fitparameters were made; the fit parameters were determined by thealgorithm.

As shown in Table 1, all test compounds inhibited NR1/NR2B glutamatereceptors. Varying degrees of inhibition were shown for the variouscompounds. Memantine, control antagonist, produced inhibition of thereceptors similar to the inhibition previously observed. Glutamate,control agonist, stimulated the receptors.

TABLE 1 IC50 values for test compounds Peak current Steady state currentCompound ID IC50 (μM) IC50 (μM) Memantine-HCl 2.96 1.14 NM-004 25.9420.96 YQW-036 10.11 6.80 Cmpd 1 4.59 2.62 Cmpd 2 73.22 47.36 Cmpd 3 8.015.08 Cmpd 4 35.24 34.24 Cmpd 5 11.22 7.18 Glutamate CRC* 2.7** 1.44**Memantine CRC* 3.51 1.68 *reference controls **EC50 is shown

Compounds 1-5 all showed activity for inhibiting the NR1/NR2B glutamatereceptor. These compounds can be useful for improving memory, awareness,and ability to perform daily functions. These compounds can be used totreat diabetes, cerebral ischemia, traumatic brain injury, stroke,epilepsy, autism spectrum disorder, a broad range of neurodegenerativeand other CNS disorders, dementia (e.g., Alzheimer's disease, vasculardementia, dementia with Lewy bodies, frontotemporal dementia andHIV-associated dementia), Huntington's disease, Parkinson's disease,multiple system atrophy (Shy-Drager syndrome), cerebellar degeneration,ataxia (e.g., cerebellar ataxia, spinocerebellar ataxia, Friedreich'sataxia and ataxia-telangiectasia [Louis-Bar syndrome]), motor neurondiseases (e.g., amyotrophic lateral sclerosis [ALS], primary lateralsclerosis [PLS], progressive muscular atrophy [PMA] and spinal muscularatrophy [SMA]), multiple sclerosis, vision impairment or loss caused byneurodegeneration of the visual pathway (e.g., optic neuropathy/atrophy,glaucoma and age-related macular degeneration), and sensorineuralhearing loss. dementia (e.g., Alzheimer's disease, vascular dementia,dementia with Lewy bodies, frontotemporal dementia and HIV-associateddementia), Huntington's disease (which often leads to dementia),Parkinson's disease (which often leads to dementia), multiple systematrophy (Shy-Drager syndrome), cerebellar degeneration, ataxia (e.g.,cerebellar ataxia, spinocerebellar ataxia, Friedreich's ataxia andataxia-telangiectasia [Louis-Bar syndrome]), motor neuron diseases(e.g., amyotrophic lateral sclerosis [ALS], primary lateral sclerosis[PLS], progressive muscular atrophy [PMA] and spinal muscular atrophy[SMA]), multiple sclerosis, vision impairment or loss caused byneurodegeneration of the visual pathway (e.g., optic neuropathy/atrophy,glaucoma and age-related macular degeneration [AMD]), and sensorineuralhearing loss.

It is understood that, while particular embodiments have beenillustrated and described, various modifications may be made thereto andare contemplated herein. It is also understood that the disclosure isnot limited by the specific examples provided herein. The descriptionand illustration of embodiments and examples of the disclosure hereinare not intended to be construed in a limiting sense. It is furtherunderstood that all aspects of the disclosure are not limited to thespecific depictions, configurations or relative proportions set forthherein, which may depend upon a variety of conditions and variables.Various modifications and variations in form and detail of theembodiments and examples of the disclosure will be apparent to a personskilled in the art. It is therefore contemplated that the disclosurealso covers any and all such modifications, variations and equivalents.

1-20. (canceled)
 21. A method of treating a central nervous system (CNS)disorder, comprising administering a therapeutically effective amount ofa compound of Formula I, wherein Formula I is:

or a pharmaceutically acceptable salt thereof.
 22. The method of claim21, wherein the CNS disorder is a neurodegenerative disorder.
 23. Themethod of claim 22, wherein the neurodegenerative disorder is dementiawith Lewy bodies or Alzheimer's disease.
 24. The method of claim 21,wherein the CNS disorder is associated with excitotoxicity.
 25. Themethod of claim 23, wherein the excitotoxicity is due to excessiveextrasynaptic glutamate.
 26. The method of claim 21, wherein the CNSdisorder is brain ischemia, traumatic brain injury, epilepsy, pain orautism spectrum disorder.
 27. The method of claim 26, wherein the CNSdisorder is an autism spectrum disorder.
 28. The method of claim 27,wherein the autism spectrum disorder is autism.
 29. The method of claim27, wherein the autism spectrum disorder is autism with elevatedglutamate.
 30. The method of claim 26, wherein the CNS disorder isepilepsy.
 31. The method of claim 26, wherein the CNS disorder istraumatic brain injury.
 32. The method of claim 26, wherein the CNSdisorder is brain ischemia.
 33. The method of claim 21, wherein the CNSdisorder is a neurodevelopmental disorder.
 34. The method of claim 33,wherein the neurodevelopmental disorder is MEF2C haploinsufficiencysyndrome.
 35. The method of claim 21, wherein the therapeuticallyeffective amount is a dose of less than 100 mg/kg per day.
 36. Themethod of claim 35, wherein the therapeutically effective amount is adose of 10 to 30 mg/kg per day.
 37. The method of claim 36, wherein thetherapeutically effective amount is a dose of 20 mg/kg per day.
 38. Themethod of claim 21, wherein the compound of Formula I is administeredorally.
 39. The method of claim 21, wherein the compound of Formula I isadministered parenterally.
 40. The method of claim 21, furthercomprising administering an additional therapeutic agent.